Doug said: Verrry helpful, Bill. Thanks. I need info like this. I've never hot rodded much less built a guitar.
I'm very happy to help. Sounds like a great build. One other thing I should mention is that the balance will change if this is done. It will probably not be a problem but it will be different (more weight towards the neck) than a stock Mustang.
If I were doing this, I'd make a CAD model of a stock Mustang and start modding it to see what my options were going to be. I could look at the CG change vs the stock guitar too. When I had something that worked, I'd compare to two for any obvious visual differences and try to hide the changes as much as possible. It seems like everything I build these days starts with a CAD model. I'd rather build it ten times in CAD and then once with real parts, like this;

This is my aluminum archtop. It has been through a bunch of necks and neck mount designs. I've kept an eye on the balance and the total weight. Some of the stuff in the model isn't visually accurate but it is accurate in terms of weight. But the main purpose for this model was to make sure it was possible to build as I envisioned it.
Best of luck on this project. Please keep us updated on your progress.........Bill