I'm ready to build a small grow room. I have a closet that is 2x4x8. I've painted it white. Will install a dual coversion ballast for MH and HPS. Ordered a 180cfm to vent into the attic

I plan to buy a hydroponic unit. How big/small can the inserts be to grow successfully. I'm looking at a Hydrofarm 15 unit system. Each pot is 5.5"x5.5".

Is a 15 unit system too big for an individual. I am looking to grow only for personal use. How much can I expect to grow per plant? I'm wondering if I would be better off with a 6 unit system? (With slightly bigger planters)?

Also, I'm assuming that about half of the plants I germinate will be male and therefore I'll only end up growing 7 or 8 plants (in the 15 unit system). Is that a reasonable assumption?

How early can the sex be determined?

Does anyone have recommendations for what seed(s) to try?
Thanks to all.
L