Guitar Neck Pocket Design

Im not sure what steps to take to ensure that a tapered neck and body designed in Shapr3d will fit perfectly. I can design the neck and the body in 2d just fine, I’m just not sure what the best way to create the matching pocket in the body using the neck profile. Is it best to design both in 2d and just extrude as necessary or is it better to extrude the body and somehow remove the intersect? All while maintaining centerline and distances for scale length.
(Ive tried it in Rhino, but prefer the Shapr3d interface. Totally different workflow).

Any suggestions would be appreciated.