I was looking at the Fb blog (there's a huge amount of info) and grow tips for their SGC says the plants need 60w to grow - and these are large yielding whoppers. Just dive in bro - 100w is certainly gonna do a job for you in a wee tent, and if you grow auto flowers all the better as these bloom up to 24 hours a day. So over time relatively small plants can produce excellent bud and a lot of it! I started growing autos late last year and though I made lots of mistakes and never got what I wanted - the money I saved growing easily covers the cost of the kit, leccy, seeds ect and smoked a lot of new to me weed. I'm not lying - I'm a stoned fool cack handed and way too keen yet these awesome plants still produce bud for me - its pretty amazing.