With those temps, I think an aircon would probably be your best bet.
In terms of yield, I run LED Quantum Boards with Samsung diodes (LM301B's) and in my small 1.2 x 0.6 tent (0.72sqm) I managed what I feel is a decent yield.
I still need to weight my Chocolope once dry, although I am expecting around 350 - 380g dry in total from my harvest. I have 4x Quantum Boards which I feel is overkill and I ran them at a max of 360W, combined they are capable of 480W with the driver I have. If you were to look at efficiency (power) and the yield from space I think it's pretty good.
28C is the max I want my grow tent to be, hotter than that and I get worried and it will negatively affect your bud as the terps will start to degrade.
Unless you acn pull in much cooler air, an aircon is probably your next best thing - a portable one will work if you can't or do not want to install a permanent mid-wall unit.
A 12 000 BTU portable aircon is around R5 - R6k brand new, 2nd hand you can get some good deals. Remember that a portable aircon requires extraction and can also act as extraction - it has a pipe which blows out hot air and this will need to be blown outside directly, the fewer bends and the shorter the run, the more effective and efficient the portable aircon will be.