Yes i just want to use ‘fast’ (auto x photo) as a mother. Yes, I really want to see if it ends early as they say and I wanted to know if I can keep it as a mother. Thank you for explaining in detail.f1's, as in auto x photo...yes, it should work, if the photo parent isn't also part auto. The F1, in this case is a valuable plant to test in depth, if starting a new line of autos. I would also test out the non-autos in the f2 generations. I did that back when i was working on making a chocolate trip into auto, challenging the girls to see if they would hermi. Root constricted, overwatered, underwatered, and light leaks...they did great. As i had challenged 11 of them, i was pretty sure that the auto sisters were going to be just as well behaved.
If you are just wanting to use a 'fast' (auto x photo) as a mother plant, for taking clones...it should work fine. I would keep them under 24 hour light, though, and make sure that they have plenty of root room.