Do i have enough room? Bubble bucket stealth grow

Ok, mid way through construction, waiting on seeds to germ atm.

This will be my first attempt at a grow and have a few questions..

dimension of he cab are 5.5 feet to the top but 4.7 to the bottom of the light at its maximum height x 4.2 x 1.9

I will be using 400 w MH for veg then 400 w HPS for flowering.. The reflector is sealed and aircooled via a Hydroponic computer fan.

Exaust consistist of 12" ducting with a 12" extractor fan blowing through a carbon filter and out the house.

Room wil have an a/c unit in it when summer arrives.

I am intending on doing a scrog, and fimming the plants at least once afer there 4th or 5th node.

My question is, will the box become to hot for 2 to 3 5 galon buckets and how far can i keep the lights off the plants?

Pictures will follow shortly, just in the process of figuring it out..