I just tried both and it seems better with more cotton, although I think you prob waste more juice using more cotton but I don't care because DIY juice is cheap. Also tried a dual coil on the IGO-W and the wire snapped so I got annoyed and used single, the airflow with 1 coil is about right so dual will prob not work as well anyway. Would be cool if a company comes out with some sort of auto dripper, for example you push the power button it drips a drip from a tank onto your coil and then heats it.