Should be fine with the 4 in., but a lot depends on the room temps where you're pulling the air from. Running the cab at night when the temps don't fluctuate so much helps.

I had a similar setup but with a smaller fan (129 cfm) and a 400 hps. In a smaller closet than yours the temps were better (not ideal, though) than in my bigger closet (their dimensions are in the first posts of my last two grow logs in my sig). Would have been much better if I had just run the last one at night but wasn't expecting such high daytime temps so early in summer.