I actually have a 400W, wish it was 600. My last grow I added a 260W HLG quantum board to it also. With that setup the temp gets in the low to mid 80's in the tent. I'm using a 10 year old 4" Sunleaves Windtunnel 4 fan, 200 cfm. The tent is 4' x 4' x 6' 6". It's a cheap tent, the tent itself is nice, but the poles are flimsy. Had to make my own frame with 2x2's for a good sturdy tent. Wrapped them with mylar.
I cannot compare the last grow with the added led to any other grow because I grew autos for the first time. Also for the last time. They grew great, yielded a lot of weed in a short grow. But crappy as far as getting high. I'll stick with photoperiods. This grow I am starting now I will be able to compare against previous grows with the hps alone since I will be doing the same as normal. I am going to grow 2 Nirvana Northern Lights, 1 Nirvana Girl Scout Cookies and 1 Nirvana AK-48. That should get me about a pound and half by mid March.