Well, the lights are up in the ceiling, and they seem to work. I replaced the incandescent lights with LEDs and got a dimmer switch for them, that all seems to work. You need a special type of dimmer for LEDs as opposed to incandescent lights, and the LEDs need to be of a type compatible with dimmers too.
The tiles are on the floor, I'm less happy about these. Despite the use by the builder of self-leveling mortar, there was a slight but noticeable hollow in one part of the floor. I compensated for this in the first line of tiles by putting extra cement under them, but it sagged a bit during the night. Not a major problem, but the next row I put in next to them at the same height sagged also, so ended up slightly lower. Not to be fooled twice, the row of tiles on the other side I raised up a little, but of course it didn't sag. The grout hides a lot of the problem, but it's not as good as I would like.