I do find if the girl's tight and I've abstained for days and days I'll come really quickly insider her. But you just never know. It is good to produce a great load over her face or tits, but that can happen with a slow build up throughout an hour's punt anyway. Abstaining for wanking is more important for me if I want two or more pops in an hour. But even then I'm probably just going to arrive dripping with precum. Once or twice I could've popped again easily, but wasn't hard enough to get it in her. I'm just a little and often person by default, I've got to put effort in to edge myself or pace a punt to only cum at the end.
What ever happens there's never any point putting pressure on yourself or worrying too much about your performance.