Opinions wanted for replacement Rear Spring selection. Thank you

You could also re-arch what you have if they are in good condition otherwise. I've re-arched jeep springs with a hydraulic press but it takes time and care. You could also add a leaf for more rate or half a leaf (cut off behind the axle with a plasma torch) for a traction aid with different clamps for the thicker stack. Most older vehicles have 2.5" wide leafs but center hole size varies. I think the Mancini XHD set would be hard to beat off the shelf for $325. If you can get the SS for little to nothing, you might pull a leaf from the middle to soften them up and drop the car a little if needed. The longer leafs are softer.