Most Helpful Girl
I'll go with out with several guys in the early stages, but I try to cut it down to 2-3 guys as soon as possible and narrow it down to the guys I really like. More than that is too much to balance, and I think it's harder to build a special connection with someone when your attention is so divided. I also won't sleep with more than one guy at the same time.
Most Helpful Guy
As many as you want. I prefer not to be exhausted, personally, so I float around 3.