The NL strains were grown and bred under lights in small spaces. These were among the most advanced indoor lines on the planet. Small growers, like many of you created them. Good work can be done with small numbers.
I'd suggest that instead of using the 3 or 4 best males as a group, you use each one individually on different buds on the plant.
Another point is that you can try making your own hybrids. This is often more rewarding than trying to clean up a line into an IBL.
I applaud Joshua's efforts to encourage everyone to breed cannabis. When everyone breeds cannabis, the genetic revolution will come. Expect miracles, they happen all the time.
N.