as for using a dual master, you may be able to get away with the single pot master by the way you plum it, if you use the single pot master with a T, just like it is but use a preassure differential switch in line of both of the front and rear lines, that way the loss of preassure on any 1 side will slam it shut and give you an ok brake pedal, and not no pedal, not perfect but it would do. there are universal fit under floor dual master cylinders you could use, but you would need to build mounts for it.