Moving to 600W+tent... advice needed

I am currently running a 150W HPS+ 162W of CFLs in a small closet space (5 sq ft +/-); I want to step my game up a bit and run a 600W HPS in a 4'X2' tent with an overall height of 48.5". I am currently able to run my 150W HPS within 8" of the plant tops without burning my ladies, in part I am running an A/C in the room keeping temps in the flower closet below 77 when the lights are on.

The tent I am looking at has 4 X 6" ports and 2 X 4" ports; I plan on running one 4" inline fan (80 CFM). I will LST and FIM top the plants during veg to keep the height down with the goal of limiting total height duing flower.

Questions:
Is 600W sufficient in the tent I want to use (8 sq ft)?
What should I reasonably expect for spacing between the lights and plant tops? Is it unreasonable to think I could keep the light at 18" with my A/C'd room without an aircooled reflector?
Should I run more than one inline fan? I will also be using a few fans within the tent for circulation.
Anything else I should consider in terms of temp control?

i have run a 600watt in a 2x4 tent and no A/C my temps were high ( 85F+ ) with winter on its way you should be ok with your A/C. you can put ducting hose from one of the

top vents to your inline fan then ether out the room or to the A/C.. do you have a hood at all? or is it just a bare bulb? run the setup befor you put your babys in to make sure

its running correct.

I will be running a reflector for sure, not a bare bulb/cooltube... What kind of inline fan/ventilation are you running on your setup? Distance between your light and COLAs?

had a 340 cfm inline with a speed controler hooked up to the hood and out the room..but i couldnt shut the tent with the light on. it whould get to hott...had the light anyware from 12 to 16 inches from the tops.