My Reply:
Why bother to know too much? so that we have an excuse if we are not bowling well? A lot of knowledge is good Provided that u can apply within the first 5 shots of yr game. If not, u be trying to experiment so much that before u know it, yr last game is up. Which is why the last Murphy's law of bowling is so apt: that u only found yr line in yr last shot.
With respect to the rubber insert. I shall not give my opinion, but rather on its uses.Rubber insert is not ebtirely made up of rubber. There are 2 types of insert. One is made of sillicone(can't remember if its is this, pls dun laugh if i got it wrong) and the other vinyl. Vinyl is "stickier",so yr finger seems "to stay longer"and this in return impart more revs. However, imagine how much stress it does to yr tendons for that split second of holding. For silicone, it smoother , that's all.
There is a standard bridge if u use inserts, becos if the bridge is too close, the fingers holes will crack as there is a lot if vibration when drilling.
Rubber insert is useful as it helps generate "lift"in the fingers and this may in turn give a little more revs. However, if u are the very passoniate bolwer who will always change rubber insert after approx 30games and have the spare $$ to spend too, otherwise, normal finger drilling is enough.In today high tech ball, u do not need to impart as much lift as olden days ball just to get more hook
