I'm in the same boat as you right now. Have had what looks like two succesful matings between my male G.rosea and two females. Theoreticaly, one mating should be enough, though I suppose there's no harm in trying again if the female looks to be willing.
I did not cohabitate either time. The first time I introduced the male into the female's enclosure and they went to it. The second time I merely placed the two enclosures side-by-side inside a larger container and the female actualy initiated by approaching the male. Both times, from introduction to male retreat couldn't have taken more than ten minutes. The first time I had to intervene to save my male, the second time she just let him go.
Yes, the female should be well fed -- both before and after mating.