I think temperature control is going to be your number one issue.

I had so many issues over the winter...and now I'm trying to maximize production through the spring as I'm scared of summer time/ heat issues for the summer time.

heat of summer...hot and then add 600 watts of HPS, plus MH on the veg side... I would suggest you try to box in a small area, like 5ft square, insulate the hell out of it, and set up A/C as part of your airflow. If you have it in the house you might be able to tap into a duct, but concern over spreading odor through out the house....

Then there is the situation with heavy ass water up attic stairs. If possible to plumb in a drain or run a hose up there....but I know alll about carrying heavy ass resevoirs of solution in my (current) low tech world, discourages proper cycles of change...if you are in hydro of any form. That said, soil I think would be more resilient to temp issues of heat and cold.

Good luck!! keep us posted