So a bit of progress today. I went on to create recesses for each plate.
I first marked where each plate was going, and then used MDF sheets to build a jig to guide the dremel plunge router base.
I started by only using guides for the long sides, but of course got carried away in one spot and went past the line, so I ended up using guides on all 4 sides:
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Was pretty tedious and took a long time, but got there.
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