for your heigth. i have mine 18 inches from plants and its 79f. If you add that to the heigth of the light you looking at about 3 1/2' max for your plants. i definately feel you would be better off with 2 600's unless your wanting a very dense SOG ( a bunch of 3' colas), man, if you can get a handle on the temp. 2 x 1000 would give you some excellant coverage. You would have some very nice, dense flowers. veg for a week or 2 max, then straight to flower, ohhhhhhhhhhhhh
nice turn around too. heres a couple pics. make sure your fan is in a sucking position, that way instead of leaks you have little vacumn hole. My fan pushes only 3' through ducting to the filter box(this part air tight with clamps) , then outside i have a 4" 170cfm cooling 2 x 1000. You might go to a 6" with a little more cfm. Use insulated ducting. and 1 pic of homemade bubbler cloner.