I think 50/50 is fine. For some guys if they pay I worry that they expect something from the girl just because he paid...
here are list of altenatives/possibilities: 40/60 - who ever eats more pays more 50/50 - safest bet, easier to work out 0/100 & 100/0 - alternate each time decider 100 / 0 - the person who chooses wot to eat pays */* - whoever can get the cash/card out quickest ?/? - whatever - mature ppl who know eachother well, don't mind whoever pays because they care about each other and won't over burden one another if they notice someone struggling throw a dice/coin - this could be an interesting game... haha
