i haven't had the guts to use ONLY my 4ft4bulb T5 for my mommies. presently i, also, utilize a 400w halide (minipulsar model).

i put my "clone" dome either 4 feet away from halide, or 2 feet under the T5, to the side.

one of these days i will turn off the halide, and see what happens with T5 only. if i were to try this, i'd switch out the 4bulber for my 6bulb4ft T5 fixture. and add another. i find that when i turn off the halide and only have the T5 on, it seems dark, lol.

i find that the T5 is GREAT for vegging in 4" pots until i transplant into 2, 3 or 5 gal pots using ocean forest potting soil, and send to flower zone.

i recently switched from fox farm nutrients, to humbolt organics.

i hope for a yield of 300-400g per meter squared. i use 2 600 sodiums, and one 400 sodium for flower time.

i think two T5 will work for you as long as you keep the moms' height under control, and rotate them around throughout the week.

always remember this about ventilation...
Fresh air is your friend!!