Tight nocks can cause problems with tuning, plus add noise. The simple solution, IMO, is get your string from a reputable string maker (not shilling here--I'm not taking orders, and won't be for a while yet). It's no great feat to match the serving size to the type nock you shoot. That way you don't risk weakening a nock, and the fit will be consistent every time.
The way I look at it is this: You don't buy a suit that's way too big or small, then take it to be altered. You don't buy shoes that are too big or too small then stuff them or put them on a stretcher. You are paying good money, so get the size that fits.
I realize a lot of bows come with "one size fits all" strings. For a small investment, you can get a string that not only gives you a proper nock fit, but will usually give you a better feel and better performance from your bow.
The string is your bow's transmission--you don't put the same transmission in a Mustang that you'd put in a Kenworth. Your bow isn't "one size fits all", your arrows aren't "one size fits all"...even your point's aren't--why should your string and serving be any different?
Chad