I think quirks should be added for every level you don't get a feat ie 2,4,5,7,8 etc. If you looked at Dragon 305 in the Faith and Honor article they present new "feats" that really should use the quirk mechanic. Would this be too much of a change from 3rd Ed? This would help solve the ongoing problem between powergamer player and "roleplayers" Players could spend their quirks on character defining items and the feats on real ability granting items. Quirks would be something you could safely ignore if you wanted to stick strictly to the 3rd edition rules treating quirks as feats as they are now.