How tight should finger inserts be? How much difference does the tightness make to the amount of lift/rotation and as a result carry you get?

i think it does make a difference. all depending on what your doing to the ball that particular time. my buddy, who's average is 225, is all about feel. even if he has a better line with one ball, he'll go to the ball that fits best in his hands. what u need to do is play around and see what u like best. whatever feel is going to get you to repeat shots time and time again is what you need to do. experimenting is absolutely crucial. just like practice, playing with pitches spans and even your finger and thumb sizes are something u should do. depending how long you have been bowling, how good u wanna be also determine this. just do some experimenting. have fun and good bowling.

I like them so that my fingers can just barely fit into the inserts, up to the first joint. This is because I have a tendency to jam my fingers all the way in, BUT when I do that, the skin just above that first joint tends to crack. It's hard to hold on the the ball with all that blood dripping all over and providing lubrication. I tend to the drop the ball when that happens. Really. Also other bowlers tend to slip on the blood on the approach; then they get pissed at me.

Storm Track -- Have you ever tried either the Magic Carpet or Thumbillow?  Both give the thumb fit enough "cushion" to minimize tape use.  --  JohnP