If you see him lock I would pull him and give him a 3 or 4 days to rest and attempt to eat, then on to the next girl. If you don't see a lock then I would give him 2 to 3 days with her, then pull him for 3 or 4 days again to rest and eat, then pair him with another. And on and on until you see ovulation or eggs.
With so many girls just keep an eye on your boy's condition, I pulled a boy last year because he was a breeding fiend but would not eat for 5 months and was looking thin, course of my 2 boys going to one of my girls, even getting pulled 2 months early, he still was the one to get the job done! Last year was my first year so I understand exactly what your going through, I think I sat next to my rack all day the first few times I paired, and when my eggs where layed, and when they 2 weeks from hatching, and 1 week, and 5 days, and 3, 2, 1... And of course I still spend a lot of time looking at my babies, and they are almost 3 months old!
If after a few pairings you haven't seen a lock, you can try putting in shed from another male to let the boy realize he might have some competition, worked for me last year = )