I used 1 of the same shoplights with 2 cool t12s for veg. worked wonderfuly for my 4 plants. When flowering came round i bought a t5 fixtur for 34 bux at home depot and am useing the worms that came with it. i have 1 warm and 1 cool in the t12 and 2 warms in the t5. and just cuz i had it laying around, i through a worm in a single balb balest form a black light. 3 of the 4 turned out male so its just the one now but its working great. 3 weeks into flower and she looks wonderfull. i gess what im getting at is i wouldnt go over 3 plants just do to space. they where getting kinda crampt.
Ive seen a few people flower with t5s with good resalts so ide upgrade. there still cheap and they put out more light. but id also keep the t12s in there too if u already have them. Good luck man