Single coils will almost undoubtedly work better; 2.0 ohm to 3.0 ohm single coil. I think the best vape in general can be had with a single coil, properly warmed. Dual coils are IMO the single largest hoax perpetrated on the unsuspecting vaper. Triple coils are even more laughable.
Dual coils need twice the total power that a single coil does to get to the same temperature, and the upper coil is almost certainly going to be less well-saturated than the lower coil, practically guaranteeing worse flavor along with the increased power consumption. Two is not always better than one. Boobs and testicles, sure. Coils, no.
I just ordered 90 Boge single coil XL stainless steel cartos for use in Smoktech 3.5ml DCT tanks. Add a trim ring so the tank won't slide down onto the 510 connector, and you're done. Unflanged cartos have the advantage of being able to be slid right into a full tank without the need to empty it first. Single coils also obviously extend battery life - 3.0 ohm single coils in particular, since they draw fewer amps.
Crystal Clear Vaping
eGo Chrome Cone for the 3.5 mL Dual Coil Tank Cartromizer