I use .210" chemcast for my edge lit signs. I always reverse the engrave and go from the back. I am most satisfied with 700 pews and 80 zooms with a 340lpi. It takes longer but it is a good balance for smaller text and thicker graphics and lines. If there is a large area of engraving I go ahead and defocus sometimes, but in general I don’t have that much of a visible engraving line. I’m happy with that.
I am almost always engraving filled vectors, but sometimes there are bitmap graphics.
Here is the result but I didn’t post settings here.