To use this plate, I cut a 1/8" drill bit in half and use the smooth part chucked up in the Dewalt.
I then use it to align the bit with the hole in the plate.
Then I raise the z and swap it out for a 1/8 bit I then zero the Z manually with a piece of paper.
Sometimes it is easier to move the X+Y one inch into the material got get a good reference area for the Z then move it back again before starting the cut.
If your using a 1/8 cutter you could probably skip some steps and align the bit to the hole.
You could probably make this with some birch plywood if your short on aluminum.
I used a 1/4" thick aluminum plate.