I get the question, however it is a limiting way to approach vaping, especially on a vv/vw device such as the evic.
Various tanks/clearos/cartos/RBAs perform differently from one another at a given resistance.
Further, based on both flavor and PG/VG ratio, some ejuices do better at higher or lower power settings.
With a single-power device, such as an eGo (non vv) or mech mod, finding an ideal resistance for the coil is more relevant than with a vv/vw device.
As long as a given coil falls within the evic's ability to fire it correctly, resistance is relatively a minor issue.
I use a number of tanks on the evic - top coil, bottom coil, dual coils, at anything from 1.6 to 3.0 ohms with good results. I pick the ejuice delivery device based on the flavor that I am vaping, and use the evic's features to to adjust to the device.