Just from my experience, I track high and clip my thumb holes on certain drillings and/or balls. I've tried the grip change per mo techniques several years ago and it caused hand issues during or after bowling after prolong use. This changes were with two differnt shops.
Anyway, I went back to my old grip till my current updated grip/span today. I was taught to adjust my rotation and tilt instead and that worked.....no more tiredness, soreness, or pain...
Btw, I'm no expert nor am I doubting Mo P's drillings techniques. I'm just speaking of experience. I just think for me, it was unnatural to position my hand/fingers in a certain way to alter my roll. Learning ti adjust my set up and/or roll was the way for me to go.