Thanks for the reply, Alan! That Cigar box model is pretty interesting, I hadn’t seen it!
You’re likely correct on swapping the casing to another model being ill advised. I am just loath to take apart a nicer model and possibly harm it with my first attempts.
Instead, I have decided to make a prototype out of pine or basswood with a 3D printed trumpet mouthpiece, of which I have several lying around. I can measure out, laser cut and engrave the case without much work, and then fit the Study 32 internals and plastic mouthpiece into it. I’ll likely leave some extra room for resonance. Then I’ll have a prototype made of cheap materials, and the patterns already made. If it works, I can purchase a nicer model and edit the case parameters accordingly to fit the internals, before repeating the process with more luxurious materials. I’ll likely go with zebra wood.