Well I did a dual coil, on a u-wick on my aga. got it to 1.5 ohms and when I fired it up, I got nothing but a bit of bubbling on the wick. Cranked it up gradually untl I reached 5 volts and got hardly any vapour at all. I rechecked contacts and ohm, but both were fine. atty got hot lol, but a huge let down. disconnected and tried each coil. 3 ohms and fired nice (all on same aga), pile of poo on duel grrr. stuck th u-wick on single coil 1.2 ohm, and vapes good for 2-3 puffs (45/55) then wait for vg to catchup lol. Not much flavour either but I think that's because I drilled an air hole above existing hole (its too high now).