Quick update.
The body was still turning out too heavy. Tomm gave me the option of continuing to decrease the mass of the mahogany body, taking the body as-is for the price of the deposit (1/2 the cost of the body) or starting over with really nicely figured -and much lighter- piece of ash that he had. I was really impressed, but I elected to continue shrinking the body.
We are going with a larger control cavity that will be twice the size of the original. Tomm is also going to be taking an inch off the butt end of the instrument. He will be dropping off the body tomorrow!
Also, I've decided to go with a BAII instead of the peavey bridge, and a set of Hipshot ultralights just arrived which should keep the bass balanced with the lighter body. Unfortunately that means that the only original t-40 parts will be the neck, neckplate, neck screws and string tree, but I'm not too disapointed. The end is near!