I got sidetracked with all of that electrical talk - not sure I followed much of it, but who knows what me brain retained. I agree with shake on the 18/6, and I'd concur with the fact it should help eliminate some of the heat problem as well as provide some dark period to focus energy on root development - here I am simply parroting what I've read on this board.

I have not read anything about it, but I wonder if dry ice may provide you some relief from the heat while adding some CO2 to the enclosed fridge? Since dry ice sublimates relatively slowly, I wonder how long a small block may last to lower your temps?

The easiest way to lower your temps may be to add additional passive air intakes with additional upper level exhaust?

Continued good luck, Smurph!