I was browsing for my next mod when I stumbled upon the Roughstack which blew me away as just plain awesome.. However I was also found the Midi Vapestack and was wondering if it was compatible with the Mini Vapestack extension MadVapes sells.. Here is some links to both. Midi Vapestack VapeStack 6 Volt Extension A reviewer on-site stated he used the extension with his Midi.. but just to be safe I was wondering if anyone here had done this.. Also I was eyeing the dimensions they listed and was curious if the Roughstack Maxi had more battery compatibility then the Midi+Extension combination. The tube was listed to support two 16340's.. Length wise when compared to a 18650 it should fit.. but it would be 2mm short in diameter.. just wondering if anyone has this extension and does a 16340 have 2mm of clearance..? Basically in a nutshell I'm looking for a mod that can take 18650 battery for all day vaping or two 16340 3 volt batteries for 6 volts or 2 18350's for 7.4 volts. Again I thank each and every one of you who takes the time to read my sorry ... problems!