Well, based on juices and clearos I've been using, I sometimes felt it needed a little more power, or was getting to much.... I start with a guess and work from there. While I am hardly an expert, I would not start at the highest setting, due to possible damage to coils. I think 3.8v is a good starting point, as that is SI's recommendation.
If it tastes burnt, take it down. If the vape or flavor is too weak, dial it up a little at a time. I can do calcs on resistance & voltage, but it is all about the flavor and vapor in the end.
If it tastes burnt, take it down. If the vape or flavor is too weak, dial it up a little at a time. I can do calcs on resistance & voltage, but it is all about the flavor and vapor in the end.