well how many lights are u running the light i sawl is 150w 11x6.8 inch (this would be a very small foot print even with 120degree lens)
2 of them would work in a 3x3 (4 for ideal)
4 of them would be good in a 4x4 (6 for ideal)
6 of them would be good in a 5x5 (8 for ideal)
as for your temps...