SCROG Cabinet Dimensions

Hi guys, I'm new to the board and have enjoyed reading through all your posts for a few weeks now. Next month I plan on constructing a cabinet for my first grow, specifically a scrog grow. At this point I'm still trying to determine how big and how many plants I plan on doing.

The cabinet I want to build would have a bottom veg chamber (2'x2'x2') and an upper flowering chamber (3'Hx2Wx2'D'). Is this an adequate space for a scrog grow?- specifically, 4 plants? I keep reading '1 plant/square foot' as a rule of thumb for scrog, but a lot of scroggers I see around here only stick to one or two plants.

Furthermore, would 4 plants under a 2'x2' scrog screen necessarily yield more than 1 or 2 under the same sized screen?

I was tentatively planning on a 400w HPS in the flowering chamber.

Let me know what you think. Thanks a lot guys.