Well there is a few problems with your plan. Pots are cheap so you mine aswell get like 6-8 pots (10$) you dont want roots intertangling. The 2 litre idea is all good, but the seed idea is a little more complicated. I totally understand you wanting to reproduce your genetics by pollinating one of your females to recreate seed, but this gets a little tricky, let me tell you why. Lets say you have 8 females and 1 mail and your looking to pollinate one of your females, the female that your looking to pollinate and the male must be placed atleast 1 sqr Mile away from your other females or those ladies will also become pollinated and produce seed instead of that lovley herb.