if in your research it doesn't say that they're made for co2 then dont consider them for high pressured co2 at all. hpa can work as long as you regulate the pressure to those similar to what you'd use with co2, say 400-600psi-ish. if running higher pressures you can expect to, at the very least, replace o'rings more frequently and lube VERY frequently. i've been lucky in that i've mostly only really have had to replace o'rings and and the odd bearing running well over 600psi.
an alternative to having a zillion 12g capsules is to get a large co2 tank and run a remote to your charger. i've done this, it works and it saves ALOT of time when trying to equalize pressure across multiple grenades (a dozen or so) when only using the 12g ones. all the functionality of the charger is intact so you can adjust the pressure when filling.
again...be VERY VERY VERY carefull when inserting super high pressure loads into the launcher!!!!! impromptu mortars are kinda scarey!!!!