Me too, that's also why I didn't just get another breeding group and restart. I want to do it myself. I started with 1m+10f, I've sold/given away hundreds and I still have hundreds ;-)
I started to have pretty nice male in F3, I'm sure I'll get there in F5. Cull the male sooner is the trick I think. You can't afford to have a bad male at large for too long ;-)
I pretty much gave away those rilis, like 15 for $10, because I don't have another tank for them.
Oh, and another thing I do is, I always have an in-tank breeder box. I grab the net when they are eating, and net the culls in the breeder box. Sell them when there are like 40-50 in there.
I just netted out 20ish males, left 2 of the best in there. The rest are living in the 75G now!
I would sell them, but labeling them "RCS" would be kinda shady.