I'm goofing around with my grip as well. I shoot well, at least for me, with the pressure of the bow at the base of the thumb; however after approx 25 shots my accuracy falls of as I feel some fatigue. If I get my palm a little more into it I find I don't notice the fatigue.
Play with it a little, then stick with what you feel works for you.
It won't always work, but if you keep changing your grip it'll be hard to know what is working and mental health, believe me I know (LOL), will become an issue.
Good Luck and ATB,
crunch