For interior lights I also wen as close to ceiling as possible. My drilled holes were so small I had to force the wire thru. FYI, I used a Black fabric covered wire (very old school look) that I found on Amazon. No grommets.
Be sure you match up your Electrical Panel with the Galley framing. I used a much lower cost Panel and had a slight interference issue. Probably because I never considered it could have an interference.
The way the Galley fits, it hides the back of your Panel pretty well. (Now if I can just resolve my Mushroom Vent leaks and Galley leaks… )
For the lights and fans, I chose as high as I could, keeping in mind you’ll have to wire around the upper lip in the rear bulkhead galley area.
I ran the rear lights and center fan through the starboard side of the shelf, then into the electrical area, under the shelf. No grommets, but EPOXY coat the holes prior to running wire. Then use flexible plastic conduit to dress the wiring.
I aimed my lower cabin lights down, not into your face, as CLC did. Use very short screws, the shelf plywood is thin!
Make sure you epoxy all holes, since condensation can be an interior issue when it’s cold outside and moist inside.