I had a similar issue, where I had a non-square shape cut out that I wanted to finish with stain before doing v-carving, so I needed to be able to place the material back on the machine and get the carving to come out where I wanted it… without being able to zero off the material. This was my solution: Wedding welcome sign
TLDR; do your v-carve for the inlay, cut out the shape you want from the wood. Do your thing with the wood (gluing, sanding, etc). Then attach scrap wood to your machine, zero off the scrap wood, and use the same vector you used to do the cutout of your wood, but cut INSIDE the line. This will result in a pocket in your scrap that exactly fits your material, in the proper orientation. Put your material in the hole and secure it. Do whatever you need to do with the material. If you need to rotate it for some reason, more scrap, cut a new hole, secure your material in it.