I just harvested my first grow which i did completly with flouros, i had a fixture with 2 20w bulbs about 2' long and a fixture about 4-5 feet tall with 2 40w grow bulbs didnt have a lot of room but it worked for me. If you have some spare fixtures and bulbs i wouldnt suggest saving them, use them all, get as much light as you can if using flouros.