I have not done any deliberate crosses myself. I've gotten a few accidental crosses that I mostly just discarded as they weren't anything to speak of.
But with the growing out , just keep growing and rouging out anything that doesn't look right. Personally for most of the hybrids I've grown out, I've seen little to no segregating. That leads one to believe that many hybrids aren't true hybrids at all but stabilized hybrids. I put up a page on my web site about that with quotes from the book Breed Your Own Vegetable Varieties by Carol Deppe -
http://knapps-fresh-vegies.netfirms....mato-info.html
If possible collect from several plants and keep some of the F - 2, 3, 4, etc, seed if possible, including some F-1 if still around. You want to be able to check the growing characteristics against something known. The reason is also you can go back if you have a problem.
Personally I was growing out Early Cascade for several generations. This year I started getting some PL plants in the latest seed I have. I think it's from mixing 2 batches of seed and 1 might have been mis-labeled. So I planted something from the 5 other batches of seed I have. I will grow them all out to compare and will save only from a batch with NO PL plants. I will have lost a grow-out or 2 but should still have something beyond F-2 seeds.
Good Luck growing,
Carol