Your drag advice needed

Lets start with what I have already: stock A body width rear end with leaf pads moved to the Mopar spring relocation location, 43 inches i believe. I also have a set of 10" wheels with 4.5 back spacing. Oh, and a stock sheetmetal 75 Duster.

I would like to run a 275 Drag Radial with at least a 1/2 lowering block, maybe an inch. I want the tire tucked, and the car slammed. Hot Rods CropDuster has the ride height im looking for. No offense to the old school cats, i grew up reading the Direct Connection catalogues.

Im also looking to do this as cheap as possible. Im thinking of using offset spring hangers, trimming the inner lip, banging the inner wheelwell dimple, and trimming the leading edge of the wheelwell to make it fit.

Questions are: what are the stock, brake mounting surface to brake mounting surface measurments on an A body rear? I will be installing billet housing ends to mount some Wilwood disc, so the rear width may need to be trimmed a bit, as well as moving the spring pads to the new offset location. What is the offset spring pad location measurements? Then, will a 10"wheel with 4.5 bs fit back there with this setup? If I have to get 8" rims with 4.5 bs because of the Drag Radial needs, this would solve most of this, correct? I was thinking of just leaving the pads as is, and going with the USCT spring relocation kit, but i *think* i would need more back spacing to get a 325 Drag Radial back there, which would add cost to the entire endeavor.

Thanks in advance