I build hollow body electrics. I typicall cut the outside shape of the instrument then cut the center out leaving a 3/4" wall thickness. I also leave some area for the neck and bridge. I have an instrument body in Easel and am trying to figure out how to do an interior offset(?) cut. This is kind of what I’m aiming for but it would be milled completely out.
You can use the offset app and then see what works for your design but best would be draw it out in ai it use fusion 360 if you need it to be what you are looking for it to be like spot on with measurements and any custom milling toolpaths that easl isn’t able to do.
Draw the body in CAD and Import it into Easel.