I did the isomat foam and athletic wrap tape on a rifle years ago. I have some small sheets of kydex sitting in my garage now that I ordered on Amazon. When I have time I’m going to try and make a decent looking adjustable cheek piece. I’ll post it if it’s a success.
Same here, used a neoprene shell holder but used foam sleeping pad strips to build up to the right height. Its light and does not absorb water and its cheap.
I bought a piece of kydex on amazon and the hardware store had some "connector bolts" or "binding posts" in the furniture part of the fastener section. warmed the kydex in the oven as I don't have a heat gun.
I used both an old mouse pad and new gel shoe inserts cut into strips. This allowed me to only have a narrow strip right on top of the stock and not affect the side width of the stock. I figured out the right height for each rifle by adding or removing strips, then used athletic tape to wrap in place. I tried pipe insulation and several other things but they tended to shrink under the pressure of the tape and continued use. Not the most eye appealing but works!
I built one out of kydex for my boy's gun. He was pulling his head up to see out of either a scope or this red dot. I used a piece of card stock to make a pattern and transferred it to the kydex and cut it out. I used a heat gun down the center of the kydex and just sandwiched it over the stock and used the same furniture style bolts as mentioned above. It was a pretty simple project that only took maybe 20-30 minutes.
I used a SAM splint (thin aluminum sheet covered in 1/4 foam google it) and coban wrap. Whole project cost me $10ish bucks and dosent do anything to my synthetic stock. You can get any color coban off Amazon if you want and it dose the job well.