Most of the best cuts have come from accidental open pollination. Not specific breeding. That seems to only make fruity crap. Lol.
That's what happened to my Frankenstein, some of the earlier iterations had that great Bubba OG taste and potency. Then when I got to the 4th generation and mixed it with some of those culitvars from Europe, (Purple Haze) It started tasting like cotton candy. I'm not complaining, but I think some of the vigor is missing. It's a great potent, great tasting plant at this stage, but I'll probably select the original f1's over the newer stuff, if I do anything else with it at this point.
Obviously, I'm limited with the space and numbers thing, so that's one of those things that will be done at a later date, if at all. I've got better fish to fry at the moment. Frankenstein was my first project, and it worked out well. I'm proud of her, she's a very solid auto-flower, IMO. As good as anything I've seen out there right now. My objectives were potency and size on that project, and it came though in both regards. But she shrank some, when I crossed in the European genes. But the internoding improved somewhat, so a trade-off. Smaller, fatter cola's.
When it comes down to hunting those special pheno's, I think it's all about your starting stock, the numbers, a bit of creativity, and faith.
Your never going to make any break though, unless you take a bit of calculated risk. Cannabis didn't get where it's at today, by people always playing it safe.