Getting rid of the original 254mm (10") leading-trailing shoe drum brakes is a GREAT idea.
Doing it by installing a bottom-feeder disc conversion is not such a great idea.
If the "Cunningham" bracket is anything like the flat-steel Little Shop of Horrors bracket, it's a disaster. The caliper pins are over-worked, supporting the caliper in a way they were never designed to do.
But you didn't give me a link, and I'm too lazy to look it up. I'd think that the bracket(s) you use will depend on the rotor you use...but I've got zero experience with rear disc conversions.
Bigger drum conversions are--generally--easier, safer, and cheaper than bottom-feeder disc conversions, especially ones that disable the park brake. But 2WD is tougher than 4WD due to the five-lug axle shafts and wheels.