I’ve had no problems running standard TM pistols on Green gas in nearly 20yrs , in the height of summer you might want to drop down a bit . All my converted TM pistols run happily on propane .
YMMV .
in my experience if you want functional , the least amount of fuss and most amount of upgrade parts I’d stick with TM or at least TM based & compatible .
however , that is just my experience 👍🏼