Building Tudor/rolex
 

I recently got into servicing mechanical and automatic watches. So far I’ve done full disassembly’s; ultrasonic clean, oil, and reassemble to a few ETA movements and I’m itching for a vintage Rolex now. My question is, I’m currently looking at a full mechanical 1940 tudor movement with dial/hands and wondering if I can use a 6565 case or a 6580 case for it? I believe the dial is 28mm, or is it frowned upon to get a mechanical hand wind 1600 Cellini and modify it to fit an oyster case as well?

Frowned upon by whom?

You can do anything you like with things you own. But it will obviously not be considered a genuine product.