So in our shop, our edgebander performs a pre-mill before applying edge tape, therefore a 400mmx400mm square panel will come off the CNC at its actual size (400mmx400mm). This is fine except for when we have an edge that needs to be finished by hand (scallops, custom geometry, radiused corners, 45deg shadowline) in which case I need to set that dimension to be smaller by whatever the thickness of the edge tape is. 

Currently we're doing this manually but obviously this is going to go wrong eventually. So what is everyone else out there doing? I've thought of a few ways that involve some custom prompts but they all seem kinda clunky. Is there an elegant solution to this?