Yes, zero arch is factory height, 1” is plus one inch. They were oval track springs, so they were often run staggered because of a banked track.
The front segment is a 1/2” longer, but the overall spring length is the same, you do not run shorter front hangers with them. The wheels move about a 1/2” back, which typically centers them better in the wheel tub.
The spring rate is ~120 lb/in, which makes them stiffer than the original XHD springs (110 lb/in), but softer than the SS springs (160 lb/in). Typically handling cars are set up 120-130 lb/in for the rear springs, so stiffer than most standard factory springs but nowhere near as rough a ride as SS springs.
Front eyelet uses the 5/8 eye bolt, the rear uses a different shackle bushing than factory, I’ll have to look up the part number.
I have AFCO springs on my car that match the Mopar oval track spring specs- 1/2” longer front segment, 121 lb/in rate, zero arch. They discontinued that part # when Mopar started making the oval track springs again. I have a set of the Mopar oval tracks as well, but I haven’t run them. They’re made in Mexico and are not as good of quality as the AFCO’s. But last I checked AFCO still wasn’t making the 121 lb/in springs.
Honestly I wouldn’t mess with the Mopar oval track springs because of their hit and miss quality. I’d call
@BergmanAutoCraft, he was having springs made to the 130 lb/in spec.