Larger shoe material to the rear of the car?

Yep

They are self-energizing design. This means that as they apply, the leading shoe drags against the drum. Since the top is against a solid anchor, the shoe tries to move with the direction of the drum and rotates toward the bottom, pushing against the rear shoe. This added force applies the rear shoe harder. Since it does more of the braking, the rear shoe should be larger.

That all said, putting the bigger shoe to the rear only matters if the system IS self energizing.

Not all of them are. I'm not sure how early you have to go to find ones that aren't, but it's not that early.

1962 I believe. The earlier cars with the two cylinders on the backing plate have equal size shoes. It was in 62 (+ or - a year or so)they paid Bendix for the right to use the "servo apply" or "servo action" brake shoe apply type. They didn't want to do that and prior to that they had the two wheel cylinders and/or some pretty big drums, but they weren't as good as the Bendix system. GM had the same problem in the early 60's which is why they had some of those aluminum finned 12 inch 2-3 inch wide drums on the big cars. When they finally went to the servo action they got rid of a lot of front end weight. This is all written down somewhere on the net and makes for some interesting reading, especially the way Chrysler tried to avoid paying Bendix for the right to use their patent method. Somebody feel free to correct me on the years or names this brake method, as this is all from Memory from 40 years ago told to me by my auto shop instructor who was privy to this information as it happened in the late fifties.

My kids 62 has the dual whl cyls as did my 57.The rears are the same shoes as fronts but use a single cylinder.Rocky

I'll bet the '62 is a "C" body??

Techinacly there were no C bodies in 62.It is a 300 though.The 62 Dodge and the 61 we had had the same brake setup.Its been too many years for me to remember what brakes the 63 I had were.Rocky

Just making I'm not repeating a P.O. screw up