Scott,

I assume those driveshaft measurements are for an internal coupler.

Also if you run the new small Winters rear you will have to add some to both those figures. 1 5/8th's if I remember right but not positive on that.

1/4 to 1/2 inch float is good. Put it together without the torque tube and level the rear arms before checking. With the arms level, that is as short as the driveline will get.