My first setup think I'm gonna go with sealed hood, torn between inline vs squirrel fan for exhaust (noise), gonna try passive intake.
Goal ~2x3' cab 250-400w digi ballast, sealed hood, temps just under 90 with a heat resistant strain. I mean under IDEAL conditions get it lower, but I've seen decent results with 90 degree temps on some grows, but everything else has to be done well too. My only experience is a bunch of reading on the subject, comparing lights a billion times, still not even settled on anything in stone yet actually. But I look at alot of journals. My goal for the first grow is as much light in a tight area as I can get with temps below 90 and a 'decent' light placement. I'd say about 18" if I can get it. The canopy penetration alone of HIDs makes me want to run them, even with the temp issues involved.
To me especially in a small tent/cab, I def want to go with digi ballast and sealed hood. Then as much exhaust as possible but I also want it to be stealth not like a jet engine errupting in my dresser. Also lightproof. Lofty goals indeed, especially on a budget.