I am rather new but I am worried about 600 in a cabinet w/ a cooltube. Don't think I would attempt a 1000. Possible a tent or clost is a better idea as people suggested. If your stuck on a cabinet, I would base it off of one already on the market as the designs are probably proven.
I am actually building one now, the link is in my footer. You may see an idea you like or give me help.