Dude, that is a sweet Cabinet ! Heat a non issue? You know, I have been concerned about my decision to split the Cab in two equal size compartments. In hind sight I think I should have done what you did and split in 2/3-flower and 1/3 veg. It is too late now that I have mounted the fans, drilled holes and am about to start a grow. Lets hope that LST does the trick and I can get away with the space I have. I am using CFL to veg and flower so if I flower fairly early, and LST I think I can keep the height down.
What I have done to stop light is to mount those inner doors with Velcro at the extreme outside edge and just inside the velcro I have a strip of 1/2" weather stripping also. It is BLACK in there as well as absolutely no light escaping the Cabinet.
By the way, is that your first grow in that Cab? If you have harvested one from there already, what was the yield on 2 plants, what strain (if you don't mind sharing)
Thanks for sharing the setup, that is the closest I have seen to what I have done so far. Rep !