I disagree. I have F350s in VEX, front and rear, with the set up I've described, and there is NO vibration, ever. I have put about 650,000 miles on this set up since I did it in 1997 and it works perfect, velvet smooth and no errors and no longer break DLs and U-joints in off road touch places--especially with the ARBs. I did not change caster whatsoever in the TC-Trans, or front. I DID tilt the Dana 60-AMC-20 up about 12 degrees in the rear and that placated any vibration.
I have driven up to 80 MPH on freeways here in the states across the US and countless miles on third rate roads out of country and and then of course, offroad with no road or trails and to this time--no errors.
Just some alternative input. The double CV set up dampens all vibrations by design and works extremely well.
Robert