re: Poker & $4 NLHE Full Ring: Full ring 2NL - OOP - QQ set on wet flop
Well the 4/2 rule works when you think you're drawing (multiply your outs by 4 if you're going to see 2 streets and by 2 if only 1). So here if you think you're behind you have 10 likely outs to a boat/quads (1 Queen, and 3 9s, 10s, Js) or 20%. Since you'll be getting in good here against smaller sets occasionally you're equity against his range is going to be higher that 20%.
After that just compare you pot odds
to your equity. Equity > pot odds call. Equity < pot odds fold.
There is no way you can ever fold this hand and you shouldn't even really think about it.