It took some trial and error even after using the coil calculator to get an appropriate combination of resistance, diameter, wire type and coil length. Finally settled on SS quad core fused clapton 28x4/36 4.0 7/6 0.36 each. 22.2 A @4.0V. The 30T doesn't break a sweat. Best of all, great flavor, a pleasantly warm
vape, and the atty doesn't even get hot. There's a lot of metal to absorb heat.
What build do you use gsmit1?