I know a lot of people like their thumb hole snug. How can a person even get the ball off their thumb with it being snug? No matter how relaxed I let my thumb feel, I will hang up in it and pull the shot inside every time. If I leave it loose, relax my thumb, and cup my wrist, I get a nice quick, clean thumb exit with accuracy (to my own extent as a bowler of course.)
Side note, how tight are your finger holes/ inserts? Is there any advantage to tighter ones rather than looser ones, or is that just preference?