I went out on a first date with this woman recently and we just split the bill 50/50. It was a refreshing change of scenery. I think that should be standard so that nobody has any expectations on either side. As time goes on you can figure out how to allocate cash flow but first dates should never be 100% on one gender, unless one of them are rich (in my opinion at least.)
Strangely enough, things tend to work out better without having expectations and letting the chips fall where they may. YMMV.