Grow Cabinet Advice

This is my first time getting ready to do my first grow.
I have built a large flowering cabinet using plywood. 4' x 3' x 6'
I will be most likely fitting it with a 600W HPS and dimmable digital ballast.
Also a 4" 153cfm inline fan with carbon filter to match.

I want to build a second cabinet with 3 chambers
- seedlings/clones/vegging
- 4 moms (I like variety)
- drying

A few questions

How many plants should I flower in that 4x3 space? (My first crop will be Purple Kush)
How high and wide should I make the chambers for the moms? Would 2'x2'x34" be enough space for 4 moms?
How high does the vegging chamber need to be? Is 16" high enough?

Thanks for all advice.

I dont think youve supplied enough info to answer fully. If you need help with cabs, Stealthy is your guy. But to me that sounds like alot of stuff for one cab. How tall do you want these things to get?

Check out this cab.....https://www.rollitup.org/general-marijuana-growing/320402-stelthys-600w-hps-project-new-75.html