Numbers are your friends. The more parents you have to select from the better. I kill a lot of plants. A friend of mine has a problem with this and thinks I am crazy every time I kill one. If you can only grow 16 plants than start 16 and select the best mother and father from these 2. I have just grew like 6 though and made a selection from them due to space though or a lack of seeds cuz there at least $10 a piece and I was almost out. Males are the hard part. If I don't like a selection I will kill them and start over. Seriously at like day 50 I have just said F### it and started over. Why finish if you don't like the parents. I have also grown out seeds and not liked the out come and gave all my seeds away cuz I was not going to grow them again. I try to cross using one father from a strain I like a lot and I will cross it with at least 2 other strains so I get different outcomes. My last Photo cross was fem using Girl scout cookies (platinum cut) crossed with self, Chocolate chunk and purple diesel. The Purple diesel was the only cross I liked and I gave every thing else away. Don't grow things your not proud of.