I already run a veg room 8x8 with four t5 4bulb set ups, and 1 5kw flower room. The rafters start at 8 feet so I could go to there potentially go to about 15 feet if I wanted to use some of the attic space. I ran a 6/3 240 from my main breaker to my garage to the sub panel. I have approx 4k...