sounds good Jeff, must have been hard work taping off the binding and the thin part on the top face. I don't see the point in a master volume plus another volume but thats up to you. It will be a long reach to the lower horn to the master volume. If you don't use the tone control much no point having 2 tone pots. I'd just drill a hole for a master tone.
When you get to the wiring stage the forum wiring guru Weirdbits may be able to knock up a wiring diagram for you. He can possibly give you the option for 2 different capacitors for the tone so you have the option.
Keen to see some pics even if its primer !