There are a whole slew of variable to take into account.
Nic mg/ml, pg/vg ratio, resistance, airflow, type of delivery device, mtl/direct lung inhale, wire&coil types, temp control & so on.
Best to start a a low power setting & gradually work your way up taking a vape of three on each setting until you find what you like.
If you get a hot, harsh, funky or burnt taste turn it down.
There is no 'best or ideal' power setting to use, it is a matter of personal preference.