For anyone who maybe wants a perfect working Version with really no HW for Geralt (Hair & Beard), this Mod is the one to go. It is recommended to use it with both DLC's installed (I don't know if it would work flawless without them). It only enables HW for everything else, but completely not Geralt. Just extract the downloaded file and put it in the mods-folder (if not already there, create one in your Witcher-Gamefolder) and enjoy! No other downloads or files needed. Works fine for the DLC-Hair- and Beardstyles. In the options, set HW to ON and depending on your specs, you could also add AA and raise the HW-Quality, of course. Run Script Merger to see if there are conflicts, but there shouldn't be any.

GREAT: For a huge perfomance improvement when playing on Ultra-Settings, use Tweaks-Mod from TookaFace and set Cascade Shadowmap Size from 3072 to 2048 and also raise the Texture Memory Budget from 800 to 1600 (should be fine for a 4GB Graphics Card) or even 3200 (should be fine for a 8GB+Graphics Card). With these two changes, especially the first one, you will get a lot of FPS, even with my Haiworks-Mod enabled, set to 2x AA and Quality set to High.

The downgrade from 3072 to 2048 is visually barely noticeable, so you won't get the feeling of missing some quality but will benefit from more FPS.
I have not noticed any performance drop, as I'm playing with it on my i7 6700K and a GTX 1080Ti.

Have fun!