Lowering Coil Spring Rear Questions

[67C10Step]

I have got my truck to the point I am about to tackle disassembling the rear section for clean up, paint, and rebuild. My plan is to do a 4” static drop with springs and eventually a 2.5” static drop on the front. Got a list of questions on parts.

Trailing arm bushings - should I go polyurethane or standard moog replacement? Concerned the polys reuse the outer shell and I don’t know how successful I’ll be getting it out.

Rear springs and panyard bar - I’m thinking progressive rate springs and adjustable bar. I’ve done lots of reading but would like to know what some have used that they were happy with. How about the kits at western that come with the shocks?

Little early but let’s talk front end. I have the stock spindles, center link, power steering box and pump from a 1973 truck. Use these spindles or pop for a kit with 2.5” drop spindles? My truck is a 67 and I plan on maintaining six lug.

I pressure washed the rear frame this weekend and was happy to see only surface rust and some original paint still present.