Lowering the Rear

I am looking for advice on how I should approach lowering the rear of my 1967 Barracuda.

Current set up front:
BBP brake set up
Tubular UCA
Adjustable strut rod
BB torsion bars Mopar Performance
15x7 steel rims with 215/60/15

Current set up rear:
SS springs
BBP axles and brakes (drum)
15x7 steel rims with 255/60/15

I am going for a moderate performance handling ride. I know I need to replace my leaf springs but with what? I am loving the lower stance in the front. I have been researching the forums and learning about lower spring rates with small arches.

The rear is much too high. I am going for a tucked wheel look. The SS springs where install to fit 275/60/15's which looked great for that period of my life.





Front looks good, needs an alignment.




I like the idea of using the firm feel spring hanger which would require springs with 5/8" bolt diameter. This give you the option for stock or lowered mounting position.
Firmfeel Mopar Suspension and Steering

Do I want to run zero arch springs?
Or 120 to 130 rate with rear sway bar (which I have in the attic :))

Thanks in advance!!!!