Hoog, you might want to make mention of this on the Maxi Roughstack info. When I put my 18650 flat top in my new maxi, I noticed that the other solder trace of the switch PC board looked like it might touch the + end of my battery. I tested it with a VOM before putting on a new clearomizer and it seemed fine, but what I didn't notice was that once the button is released, the voltage dropped to 0 then started rising again. I confirmed this to be true after nearly toasting the clearomizer. I just added a magnetic spacer to the battery top and it fixed the problem.
IMO, to add a drop of solder (solder mound) to the PC board or battery top would work for awhile, but will flatten out over time and may create the problem again.
The magnetic spacer may slip eventually too, I haven't found out yet, so I would highly recommend just specifying to use tip top 18650's to keep it simple.
btw, I'm really diggin' the Maxi. Awesome mod for the money!
The solder blob tends to vary a bit with whoever build roughstacks that week. We only add the solder to protect the thin layer of tin on the pcb. Raising it up a bit by adding more solder will certainly help with the flat tops and once that is done they should work with no troubles..
hoog