veg room help

I was going to try and add a veg room to cut of a month, tell me what you think. i was going to use a baby bloomer ebb flo table with 3x3 RW cubes with a 150w hps and a pair of 2ft t5s on each side. its a small set up the closet is only 40" x 22" . My only real question is how big can i grow in 3x3 cubes i was hoping to veg for 3-4 weeks after the clones have rooted in Rw starters. any advice would be great let me know if you can think of anything that would improve the set up

so .... any ideal how long ii can grow for in a 3x3 RW cube??