Just thought I would throw in my 2 bits on the gas tank, since I am in the same situation.

When I took the old tank out of my 61, I noticed that the filler goes into the bottom left corner of the tank, just under the rear pan. It took me about 2 seconds to realize that, if I was rear-ended, and that rubber joining tube was ripped away from the tank, it would spew its contents onto the hot engine of the offender!

The weight on my 61 only covers the rear half of the tank, so if one spins the Mustang tank around, and uses the existing filler, or moved the filler to the middle of the tank, it can be accessed through a hole in the box floor. A bit harder to reach, but safer.