Be sure to thoroughly prime the new/unused head.
As far as what settings go, the standard evic mini doesn't have a SS temp control mode so use watt mode.
Same as any other delivery device, start off at a low power setting & work your way up until you find what you like.
MTL is gonna be a little finicky using .25Ω and enough airflow to keep from burning the wicking material.
What nic mg/ml are you using?