Most of the time with the adjustable pinion snubber, you have to cut it down so it winds up being just a little taller than the factory stock pinion snubber.
The ONLY thing a snubber is good for is to limit the upward travel of the yoke so that it doesn't put the rear joint in a bind. But if you put the snubber close enough to the bottom of the car to actually prevent that, it hits on every bump so the car rides like a log wagon.
Snubbers do nothing for traction if that is the goal. That is the job of the front segment of the leafs along with the proper shocks.
Years ago a friend of mine was following me in my 70 Challenger as we were getting on the freeway. Basically stock with factory sway bars front and rear with the 440/426 extra heavy duty leaf springs and Monroe shocks (no fancy shocks back then). His words, "On the freeway on ramp, your back end sucked down several inches and you were f---ing gone!"
A little taller than stock pinion snubber probably would have helped a little with the "suck down"!