Not a mech wizard at all, although I do of course have a few in the vapocalpyse box....
But I've always read that the builder should shoot for the (equivalent) watts of what they prefer when calculating for 3.8 volts. Lions tend to drop off the full charge 4.2 fairly quickly, settle around 3.8 for a long time, then fall off from there quickly. So whatever resistance would give your preferred vape at 3.8 volts is what to build for.
But I've always read that the builder should shoot for the (equivalent) watts of what they prefer when calculating for 3.8 volts. Lions tend to drop off the full charge 4.2 fairly quickly, settle around 3.8 for a long time, then fall off from there quickly. So whatever resistance would give your preferred vape at 3.8 volts is what to build for.