God dammit. I just typed out 6 paragraphs of gold inspired by your words of encouragement, and I saw a update notice on my computer, I clicked on it to suspend it, and instead of giving me the option of suspending it, it just went ahead and shut down everything without saving and updated itself. God fucking dammit.
Anyways, air conditioning: I think a squirrel cage blower attached to the outside of the unit you built would make a huge difference. Remember, if it is making excessive heat, it is using excessive power. Any time you are stressing electronics you bring it from where it "idles" to it's maximum output. Just like in my old job, we would make TV's in the store as bright and colorful as possible using a setting called "Vivid Mode" and a high end 50" Plasma (Plasma rules btw, fuck LED, unless it's that new Sharp Elite, yes, Sharp is making the new Elite series) errr, anyways, a high end 50" Plasma may draw 394w on Vivid mode, which isn't a power sucker for a 50" but still more than the new standard, you go ahead and put this television on a proper setting made for the home, like "Standard Mode" or "Movie Mode" and the power would drop down to 130w of power consistently, and peak out at about 200w, better than maxing out at 394w and normally pulling 300w. Heat = workload in electronics, and workload = money.
Anyways, I have played with 6" and 8" inline fans: a high quality 6" inline fan can pull 450 cfm at 75w, while a low quality 8" inline fan can pull as low as 550cfm at 150w, not including all the twists and turns in your system. So what I am saying here, as a ground rule, is don't spend a dime unless you are spending it on the best. a 8" high quality fan can easily pull 800cfm at the same 150w, but if you are buying cheap crap, you might as well just buy duct booster to put inbetween your 6" inline fans. a 6" duct booster easily pulls 240 cfm with 30w of power, for 30 dollars.
Going from to a high end 8" inline fan, there is a huge difference in draw and temperature, just make Vortex/Can your minimum standard, and you will do fine. I will get some recommendations from my buddy who tests everything for the local dro store, he has a list of fans that are high velocity and very very quiet, and best of all, have a reliable bearing. Bearings seems to go as fast as the carbon filters do from Hydrofarm, and most people get them replaced every 2 years because they get very loud, buying a high quality fan will help avoid this until it gets near that 5 year mark like printed on its guarantee. All larger fans are going to need more replacing on the bearings. I use a 8" inline fan right now in my room with 6" fixtures and it makes a huge difference over a 6" fan. You absolutely can port 800cfm of air through a 6" tube, no problem, there is not an issue reducing down all your tubing so everything matches up to your 6" cool tubes. The fact that it is 8" just makes everything easy to match up, for both you and the manufacturer, but you don't need to keep it at 8".
Anyways, now that I have moved I need to dumb my garden down from 70 plants to 6 and 12, maybe 12 and 24 since I have a few extra recommendations here. Then I will post a more legal journal for us all to enjoy. Hopefully we upgrade to a 3 bedroom house from this apartment real soon so I can post DIY projects, I fucking love my nail gun. I am letting my grow partners at my old place sort out the males and the weaker "give away" plants, and hopefully after all that we have 30-40 plants to share, which will be more than enough for both of us. After I get rid of some of these exotic varieties and choose which seeds I will be ordering again I will go ahead and start using my own seeds that I breed. I think as of right now though, TGA's Chernobyl and Dairy Queen are staying, Jedi Kush is staying, Sour Diesel is probably going and will come back another time, Rock Lock is going, Diablo OG is going, Blackberry is staying, LA Confidential is undecided, White Berry is staying, Hazy OG is staying and will never leave my side, it might even replace the SFV OG, I need to try the final product though. In the next week or two, I am having a very special delivery of real Fire OG cuts, and some cool cuts and seeds of some other strains I have had my eye on for a long time. Master Kush came down last week, I am done with that, mold resistant my ass.