I used the '73 C-body rotors (and calipers) just because I had them on the shelf for other discbrake conversions. And they are fairly cheap.

The C-rotors are 1.25" thick and 11.75" in diameter, the same as the Cordoba-rotors I believe (although not sure about the thickness).
C-body calipers have a large 2.75" piston diameter.

One thing different on the C-rotors is the outer bearing size. It's larger so the spindle needs a sleeve to make it thicker to carry the larger C-body bearing.
I used Cordoba/Charger caliper-brackets, which were spaced on the spindle by 2 simple large washers.

The rotor-change didn't alter anything in the suspension or steering-linkage. It just mounted in place of the stock rotor.
But I would not advice to copy this swap to the dot, as it didn't make things lighter upfront.

Here's some more info about what I did;
https://www.bigblockmopar.nl/2012/06/dart-discbrake-upgrade/

I'm currently looking options of loosing the heavy brake calipers and brackets, and install a lightweight caliper.