Somebody looking for that house couldn't read the cursive where the number is spelled out.

As soon as possible. And you would be better off getting a product called table top epoxy.

The calculation is correct, but some led lights dim using pulse width modulation instead of the voltage regulation used in incandescent bulbs of the past.

Pulse width modulation works by taking an led that's "flashing" 60,000 a second and makes it half as bright by flashing on and off 60,000 a second resulting in it being on for 30,000 pulses and giving off half the light.

You need to know if the led lights are "dimmable" i.e. they have the dimmer in the bulb or if the led light is relying on the dimmer switch to provide the modulation for the bulbs.

If it's not level you wind up sticking things together at angles that are slightly different from 90 degrees. In a small space it's not a big deal. In a large space you wind up with gaps and overlaps as you move across the room.

Lexis Nexis or some other similar service that normal people can't afford.

It can be done, but any method you use to cut the internal hole is going to leave a gap about the width of the saw blade, router bit or laser beam width. If you want it cut perfectly you are going to want to use a cnc laser cutter.