Nice!
Seems I read somewhere one time that in a Foxbody they have to add bracing to the floor as well. Seems that while a good seat can hold you well, in the Rustang the seat itself moves around a bunch and they lose some of the benefits of the good seat.
Not sure if our cars could have a similar problem, but might be something to think about as you are working this in.
Can't wait to see how you come up with a quick disconnect so you can swap between the 2 seats. :D
I was teasing a buddy last weekend about this. He has a BB Dart and a '67 Belvedere and only one set of seats. I told him he needed to figure out how to make the seats swappable between the 2 so he doesn't have to spend money on a second interior.