Well I switched from the fork grip to the power grip because my pinky finger was hurting (the joint closest to the end of the finger) from smushing it into the rim with my ring finger. Managed to get some good spin with no flutter with the power grip (putters and mids) two days ago after an hour of practice... thought I had it all figured out, although my thumb wasn't "thumb forward" and I wasn't getting any increased distance, just lots of extra spin.
Well I tried the same thing again yesterday, and just could not duplicate what I was doing two days ago. It might be because my x-step still isn't consistent... in any case, I'm going to try switching back to the fork grip because throwing my mids was easier with that. Hopefully I won't hurt my pinky finger again. Also gonna try switching my power grip back to more thumb forward, I was getting less spin but at one point my throws were actually fairly consistent with that.
My goal was to have consistent throws (not necessarily big D or accurate) with proper technique by the beginning of the cold weather.... I guess that's not going to happen
EDIT: Also, I notice that when I use the power grip my middle, ring, and pinky fingers have their tips pushed against the rim of the disc... not really their pads. I think this might cause problems when the disc tries to rip out of my hand... it definitely doesn't look like the grip it to rip it article. Maybe I need to be using the fork grip for that reason (even with drivers), the fork grip allows the pad of my pinky finger to be in contact with the rim.