Fantastic thread, Yipyip.  It was really helpful for me.  Even though I'm not technically a newbie, there is a lot to learn in mining coins.  I've tried the Add2PSU device and found that I couldn't get it to work.  2nd PSU would blip on really fast and then shut right off.  At one point, as I was fiddling with everything, I hit the power switch and saw a small puff of smoke come up from the motherboard right in front of my face from a tiny (literally .5mm^2) chip on the MB.  I thought "crap I've fried my $200 MB" but restored the cabling to it's original config (removing the 2nd PSU from the system) and it booted up just like normal - whew!

Based on your advice, I'm going to invest some coins to get a new 1500W PSU (my main one is a 1000W, good for running 3 video cards and that's about it).

I also thought it impressive you managed to cool your rigs when temps outside were 100+ deg F without air conditioning.  Very impressive :-)

Cheers, mate.