As I do a lot of masking, one thing I've run into is exactly the best way to set up certain aspects of the shot to make it easy to mask.

A rim light for example really helps define the body lines against a background. Not bad for hair.

But that's not always a possibility. A lot of the stuff I shoot for masking is single light noir style. Often the lighting comes out very nice on the skin, the composition goes well, but then I'm left with hair that just won't separate well and I really have to fudge around with it because it's come away ragged or patchy.

I've tried the following masking methods:

Topaz REmask 3 (my favorite)
Vertus fluid mask - fairly useless.
using photoshops refine mask - 8 times out of 10 it doesn't help.

I've tried dark backgrounds and light backgrounds.

Dark backgrounds are better for the models body. Most of my models are wearing lighter color clothes, and they mask better against a dark background, but some of the models have dark hair and some light hair. The light hair can mask well against a dark background, but obviously black hair doesn't mask well against a black background.

When the hair moves during movement shots we end up dealing with patches of light which come through the hair, and its of background. The masking plugins allow me to deal with it sometimes, but I find they leave it patchy and looking weird. I'll try and put up a sample of that later. This isn't simply an issue of a few flying hairs, I'm talking about masking hair where the model has whipped their head around, or say a fan might be involved, significant movement so simply saying "Make sure it's combed and shaped" won't really help.

Higher flash sync speeds...
Throught TTL HSS(high speed sync) or Pocketwizard HyperSync or Lens with Leaf Shutter.

Topaz is my preferred too, but Vertus is not useless if you got strong contrast
between the FG(foreground) and the BG(background)like a blond girl with white
dress in a dark BG https://youtu.be/VXz-sawg864
My problem with Vertus is that it is not a true x64 plug-in so it can not handle
16-bit BIG images...

Shooting hair successfully... and expecting to get single hair strand accuracy... requires you to optimize quite a number of factors.

I use both Fluid Mask and Topaz.

Here are some of the things I keep in mind when shooting for high precision hair cutouts. 

1. The color of the hair you are shooting can make a big difference in your success rate.   Black hair is the easiest hair color to get great cutout results with.  Brown hair is excellent to work with .  Red hair cuts out pretty good as well.   BUT...Blond hair almost always seems to be a nightmare to cutout easily...especially if you have any kind of side, top,  or back lighting.  If im shooting blond hair and expecting great cutouts...I will almost never want to use a hair light on the original shoot.   I will add in the hair highlights later on in post production.  The Problem with blond hair is that it is sometimes translucent... or even see through... at the edges.  You can have almost black looking hair at the roots sometimes, yellow blond hair in the middle, and then some transparent or translucent hair areas near the ends... and then... some really bright... almost white highlights... at the edges.  Cutting out these many varying colors... with so many luminance transitions...over a complex background at the edges...can create real problems for your extraction software.   Black hair does not readily re-transmit or refract the light behind it... so it is easier to accurately find the edges with black or brown hair.  But Blond hair is sometimes transparent or translucent... and its color can change from dark,  to yellow,  to white along its length  Thats why software has a tough time with Blond hair...too many subtle changes to calculate.

2.  Keep your model 5-6 feet away from the background.   If you can keep your model 5 or 6 feet away from the background then you can get better results it seems.   If she is too close to the background... then her own shadow will fall onto the fine edges of her hair. This will darken up the fine details at the edges of the hair and it will make it much harder to cut out.    By moving your model forward some...you will also minimize the background color from bouncing and splashing back onto the model from the rear.  This strong blowback of the background color can also contaminate the hair edges...making it harder to cutout. 

3.  Use a light battleship gray, a chroma key green. or chroma key blue background if you can.    Each of these colors makes the cutting out much easier.  Also, make sure the background is SMOOTH in texture and uniformly lit.  TEXTURES or tight patterns in the background will create complex interactions with the hair edges...and make it much more difficult to identify, isolate, and cut the hair strands out.   Pine trees, bushes, brick walls, etc. or other complex backgrounds make it nearly impossible for the software to differentiate the edges of the hair and make good cutouts later on.  If you know you might be cutting out this image...make sure you try to optimize the backgrounds in the Original Image to make your life easier later on!   You can use almost any single color for the background if you need to... as long as it is smooth, and uniformly lit, without dark shadows, or complex patterns at the hair edges.  Keep the backgrounds simple and smooth for best results.

4.  Your Cutout Software must be able to clearly "SEE" and differentiate your hair edges.   Your software needs to have clean, clear edges to do its job the best.  There are 3 things that that will help your software see the edges better: luminance differences, color differences, and saturation differences.  Your software will use these 3 factors to tell where the hair is...and where the background is.  SO...help it see better!

Make sure you have a background that has a different LUMINANCE level from the hair!!! If the background is a little brighter or darker than the hair strands...then it will be able to differentiate where to cut the hair.  This creates visual separation and contrast between the flyaway hairs and the background.  Besides luminance contrast, your cutout software can also use color differences to tell where your hair is and where the background is.  So, Choose a BACKGROUND COLOR  that is very distinct compared to the hair color.   Dont use yellow or tan backgrounds for blonds for example.  Choose a strongly contrasting color for your background to give your software a clear signal of where the hair  is...and where the background is. .  Choose a fairly HIGH SATURATION COLOR for the background color so that the software can better differentiate between the hair and the background.  Vertus Mask for example, works by looking for luminosity transitions to help itself find the hair edges, it uses high contrast edges to see clearer, it uses color hue to tell the difference between the hair and the background, and it uses different saturation levels to tell where the hair is and where the background is. 

5.  Light your background evenly... but NOT TOO STRONGLY! Too much light shining on the background will create a color bounce back from the background...and it will look like your model is being backlit by the background color.   In the case of a blond haired model...this is terrible trouble.  The translucent and the see through parts of the blond hair will pick up this color cast... and your software will think that your hair is now a part of the background itself... and you will get a big blob or a big ugly hole at the edges.  Thats one reason why blond hair cuts out so poorly.   Black, brown, and red haired models always seem to cut out better, becaue they are not translucent and they dont contaminate as easily. 

Keeping the light even on your smooth contrasty background is great...BUT dont "Over Power" the light level.  The background light level should be approximately 3/4 to 1 stop brighter or darker than your face meter reading.  Too much background light level can cause color casts, and color bounce, and contamination of the fine detail hair edges.   Sometimes shooting against a cloudless blue sky can get you some nice cutouts too in a pinch if you can manage that.

I am able to get single strand hair cutouts rather easily with Fluid Mask as long as I keep the preceding rules in mind.  Our extraction software has to be able to SEE almost as good as your own human eye does (or better even) to get a good cutout for you.  Try to optimize your original shots so that it cooperates with the way that the extraction software works best.

So...In Recap... Remember:    Make the backgrounds smooth, with no complex textures, make the lighting even, and not overly bright. Try to create a difference in luminance levels between the lightness or darkness of the hair and the brightness of the background (this will be a   B  I  G   help).  Try to use light gray... or a nice color hue difference for your background color... so the software can find the background color between hair strands very easily!  And try to give your background some saturation so your software can have something else to key off of.    Also, you can use a fast shutter speed or strobes so you minimize hair blurring or motion at the edges, try to keep fine hair in focus for best extraction, and use a prime lens for best detail and contrast.  You can also use the clarity slider in Adobe Camera Raw to get some additional mid level contrast and extra detail... as well as mild sharpening just before you create the cutout.  Be sure to use the blue blending brush with Fluid Mask and use the "Smart" blending option to get single hair strand accuracy.

I rarely ever seem to get great flyaway hair cutouts with Photoshop itself unfortunately...even using channels and refine edges.  Unless the hair edges are smooth themselves...Photoshop still has a tough time doing the finest details still.  For simpler edge finding its great...and getting better all the time.   The new 3DLUT Look Up Table program has a masking feature built into it...and it may also be useful as a masking tool someday.

Sorry to be so long.  But getting accurate cutouts with flyaway hair can be really frustrating... especially if you dont create the best edge contrast possible to begin with...so the software knows when to start and stop its transparency magic.  Confusion in = Confusion Out.   So, shoot the shot right to begin with... that way you can get the best extraction results.