a mate runs 600watts in a smaller space than that and he has problams with heat his canopy sits at around 29-30 which is to hot, i wuda sayed go for 6 inch but just try wat you got for now.
temp makes them a pain bro when its cold out side its cold in your room when its hot its hot but if you fully insulate it it should be ok you might need a bigger exhaust aswell
to much of a random question but in a aqua farm you should do 16 oz if done properly . then again these type of questions depend to much on how experianced the grower is
just water it and drop the temps should be fine if its not fried an the leafs are still green. hps will dry your soil out much quicker maby its time for a repot
there was some shit on here a few weeks ago about them frauding cards i think its bullshit myself iv never had a problam but get a prepaid card if it makes u sleep better