Without knowing exactly how you’re modifying your settings I’m going to start from scratch.
First - in the interest of ease, I’d cut the covering off a pen and tape it down to a piece of waste material.
Second - Since you know it takes a pretty light touch I’d set up an engrave test that starts at literally 1 power and goes up in increments of 1 to 10 with 270lpi and probably 1000 speed. A test would literally be just a block of colour maybe 1/8" square. Line up 10 of those, and manually change just the power.
Third - Decide which of those 10 you like the best
Fourth - Decide if you’d like the one you picked more if it were just deeper/lighter/whatever
Last - adjust lpi or speed to refine your actual final setting
