i myself tried no finger grips and didnt like it.  the size of your singer(insert - inside) will be the new hole size and as far as the bridge (i'm not a driller just going off what i remember from my driller) any smaller and you tend to have a breakout or a higher chance of it.

I thought with droping the grips that would stop some of the maint cost of bowling --- replacing grips 1,2, 3 times a yr. but it didn't pan out for me no big loss but if ya do it good luck with it.

Ask your driller to measure your fingers for the correct fit without grips.  As the others have said, making the bridge narrower increases the chance for cracking.  --  JohnP

I'm in the process of going back to no grips as well.. (about 15 balls to plug and redrill).  Main reason for me was physical the grips were just destroying my fingers as I tended to force my fingers in a little and then reset them so the sides of my fingers below the 1st knuckle would blister and tear open over time. It wouldn't matter much if I just bowled league casually but when your bowling 50 to 100 games a week, it's a lot of wear and tear for me.  Another benefit for me is that the feel is more consistent ball to ball without grips and it seems I have more 'feel' during the release itself.  My release feels a touch 'cleaner' without grips... almost like the difference between graphite shafts and steel shafts in golf irons.  Norm Duke has mentioned some of the same reasons why he chooses not to use inserts in his equipment as well.  I also thought my rev rate would drop a little but so far I haven't noticed any significant difference.