Tool Diameter Offsets or Better Method for Making Inlays

So I worked at this somewhere around 12 hours yesterday ending around 3:30am today. As it turns out much of my struggle was with a poor design in fusion. After getting that ironed out it only took a few attempts and logging results to get a killer fit. I'm still trying to understand just what's happening when using crc at the mill, but for now at least i can make it work.

This is a square pocket with an island, then a square donut. I could press them all the way together but would never get them apart. So today it's back to the mission of inlaying a mahogany heart in an oak box lid.

image missing https://i.imgur.com/sXNr1pz.jpg

If you use an angled bit (like 15 degrees) for the walls of the pocket and the insert it will be more forgiving for size errors when doing inlays

I think part of the problem might have been using a GRBL post, and I don't think that GRBL supports the G41 / G42 codes:
linuxcnc.org/docs/stable/html/gcode/g-code.html#gcode:g41-g42

I think you're correct on the G41/G42 and grbl.my ProVer 4030 did weird things until I told QCAD/CAM to use the GRBL thing.