Use the Ohm's law formula as a starting point, with the standard for mech mods... 4.2V as you constant.
- For wattage ("Power") the formula is V² ÷ Ω = P.
- For amperage ("Current") the formula is V ÷ Ω = C.
So, for your 0.3Ω build, start with 59 watts... and go up from there, until it's vaping where you like it, or is burning wick... which ever comes first.
Remember that calculated wattage
doesn't care about your wire gauge or coils in parallel count... just the net resistance and battery voltage.
Heat flux
does care about the wire gauge (and net surface area), coils in parallel count and net resistance, and is directly affected by them, both together
and independently.
Heat flux is the coil(s) radiant heat, expressed in milliwatts per millimeter of coil surface area... squared. For our purposes... it's simply how warm you perceive your vape to be.