Semi/Permanently setting Hicapa hopup
 

If I set my hopup high, almost to max or to max (which I usually do because I shoot at least 0.25g) it resets after a few shots to something less. I know I can always loctite/epoxy the hopup knob in place, but then it's not adjustable for 0.25/0.28

Does anyone have some other good suggestions?

Stiffen up the metal arm that holds the hicapa.
If not, what I did was hot glue about 2mm thick on the wheel to make a stop.
Make sure you remove the oil around it. You can easily remove it if you don't want it no more.

Another option is getting a new rubber, I got the purple Nine Ball one and it stiffen up my wheel.

Amen to that. Another thing that might work would be shimming your adjustment wheel. I know on my KJW KP-06 (thanks again, Styrak), I have a shim in there and just crank the screws nice and tight when I have it all dialed in - tends to hold up pretty well... at least until I decide to do a daily cleaning of it all. God, I need a life.

I have a fairly new Firefly soft hopup rubber in there.

I'll try the shimming idea, and if all else fails I'll try some glue at almost max hop.

Use blue loctite, its non permanency is its purpose. A very small amount around the bolt head is all you need. BUT your going to want to clean it off occasionally.