mark
+1y
keep in mind some mazda pick-ups came with 1peice driveshafts (yea blare you're gay)
it would be a lot easier to work with a 1peice shaft since you can only shorten itself, rather than choosing to shorten the 1st or 2nd shaft. Plus it would also be easier to setup your pinion.
but if you want to stick with the 2peice, shorten the 2nd shaft so you dont have to move the carrier bearing assembly. what i would do also since you are using a 2link is that try to mount the 2link bars as close to the carrier bearing as you can, so it will not shove it in unlike the stock leaf perch mounted 2links
at the stock position of the carrier bearing assembly, you'll feel vibration at starting from stand still no matter what link setup you have because the 2nd shaft angle is so high when the truck is layed out, i know mine sits at about 15-25degrees when im layed out with reference to the 1st shaft, that is really bad. what you can do is move the carrier bearing assembly up to lessen the angle, and to make up for the changed angle in the 1st shaft, shim up the tranny end (I.E. move the carrier up 2inches, move the tranny up half inch, this will set your 1st shaft angle near zero, this lessens the angle change at the carrier ujoint caused by the 2nd shaft moving up and down, the 2nd shaft angle will drop to less than 10degrees layed out, compared to the typical 20something degrees
had a 2link and 4link, both only vibrated when i started to move from stop at a really low height, pretty much half inch off the ground, the 4link vibrates less because the pinion was good on the axle ujoint, but it's all the carrier bearing being at a really bad angle causing it to bind where the vibration comes from
sorry for the book