I have a mini using 3.0-3.2 right now... too cool at 3.7 and too hot at 5v...exactly why I can't wait for my Buzz I'm guessing closer to 4 would be good. I picked up a couple of regular MAP tanks in anticipation of my Buzz getting here... Also read that the fluxomizers are in at 3.5-3.6 ohm and may give them a whirl. I would build one of those DIY tanks if I had time, maybe some weekend I'll give it a try after I find the parts I need.