I typically wait between 10-14 days just so the recovery time for the female is shorter.
When you are stripping fry, try using a paperclip or something similar to gently pry open the bottom part of the fishes jaw. BE CAREFUL! You don't want to damage their jaw by pulling it down too far, so take your time.
Typically, I will get a shallow container (think cool whip container) and fill it with tank water. I will then put the female in there, and hold her at a slight downward angle and open her mouth. If it seems like there are fry in there that don't want to come out, I'll pull her out of the water (still with her head down and mouth open) a couple of times to let gravity do the trick.