Replacing the original leaf springs w/ 5 leaf springs and urethane bushings/pads. Looks like the stock u/t-bolts are about a half inch too short so I've ordered a new hardware kit from Ames
Should the shock mount bracket be snug against the spring perch? I have 3/4" gap assuming the urethane does not compress when I am able to bolt it together.
They do not neccessarily have to be tight against the perches. In fact if it touches before you get it tightened all the way your spring may end up loose and just floating around in there.
With rubber the gap will close as it relaxes. Not sure about urethane? I would keep an eye on the shock mounting pads and every other day tighten it a little more until you get the to plates together. with a gap the stress on the bolts could increase and fail.