@brinemobee: Blenderallday’s method is the easiest way to engrave on any surface. Just blur your image (A lot!) to have smoother edges. The engraving won’t have vertical walls any more but you won’t need to set the Subsurf modifier so high.
If you really insist on having some real geometry, there is however a way. I found an interesting way to engrave text on a flat surface on YouTube. I wanted to see if it would work on a curved surface. Here is what I made:
I didn’t work much on the geometry so there are places where the result isn’t perfect. But the other places where it’s so perfect show that it’s possible… with a bit of work.
As you can see, the geometry is a real mess full of triangles. To have only quads is impossible but, at least, it’s possible to do more than just [ALT J] (Triangles to Quads) like I did.
If somebody is really interested (and has a big stock of tuna cans in their basement), I’ll explain. That’s a lot of work!