hmm, interesting.. I've never tried growing 12/12 from seed.. It will be interesting to see what the yield and quality of the bud will be once you harvest... I do see some of the advantages in that list, like space, electricity cost, easy maintenance, etc BUT while it is true that environmental factors do play a part in plant sex, it is mostly determined by the genetics of the seed, so normally 50/50 chance depending on the variety; I am not aware of any scientific data showing that 12/12 photoperiod from germination increases the likelyhood of the plants turning female.
Also, I have a feeling that the 20-40 days from now until harvest is wishful thinking.. the plant must fully mature (which means alternating node/branch development) before the buds will mature and that takes at least 5 weeks for most strains.. so if they are a month old now, and estimating about 40 days for flowering, I would say that you probably have at least 5-6 weeks until harvest.
Yea, bagseed is fine and sometimes great to grow and smoke ; check out my experiment with bagseed -->
https://www.rollitup.org/grow-journals/129998-consciousness420s-random-bagseed-hydro-grow.html