Are you resting your palm on the desk? That's the only way I can think that you might be straining your wrist.

If so...

1. Ideally, you shouldn't be resting your wrist/palm while typing or gaming. This causes strain as you're describing.
2. A wrist rest is not the correct solution. These are meant for resting your palms while you are not typing. While typing or gaming, they will restrict your hand movement and possibly cause more strain if your palm remains stationary.
3. If possible, try moving your keyboard deeper into your desk. This allows you to rest your upper forearm on the edge of the desk and act as a pivot point which should give you the height you need for a proper typing (or gaming) experience.

I definitely want more clamp from my HD800, which practically falls off my head if tilt it in any way.

The Dekoni pads for the HD800 are the most comfortable for me in that regard, but the seal feels a bit weird with their foam choice. The sound also leaves something to be desired - I'm not a big fan of the Dekoni HD800 pads without DSP/EQ.

Seeing the thickness and softness of the HD800 sub pads in ZMF's videos, they seem to have done a really nice job and I'm excited that their fit might be the perfect middle ground for me.

As for sound, ZMF did very well with the 6XX sub pads, another headphone that is hard to get the aftermarket pads "right" on, so that gives me confidence they pulled it off with the HD800. I've been really enjoying the suede version on my 6XX.

All in all, I've ordered both types of pads, and I'm really looking forward to hearing (and feeling) what ZMF has to offer my HD800.