Rackoon: I use 1/8" plexi for my CP top and with the plexi I have a simple 3" hole with the lip of the plexi rounded. Playing Centipede, for example, you don't even notice the 1/8" lip... playing Golden Tee or Bowling, MOST of the time you don't even notice the 1/8" lip, but ONCE in a while your finger will rub on it, not bad mind you.
At 1/4", I am not sure how bad it would be...bad i'd imagine...but maybe you can either bevel the edge down or get it rounded VERY smooth. Also, why use 1/4" thick glass, that is a bit thick. My Atari cocktail cabinet uses 3/16" and that's decently thick...and heavy.