I have 3 32-20s, but I don't have any favorite loads handy. A case full of 3-f and a BP lubed cast bullet would be a good choice. It's what I use for the '89 Marlin. I used to use a moderate charge of Unique for my SAA, don't remember the exact load. I try to avoid getting the BP loads mixed up with smokeless, since the S&W DA is kinda hard to clean BP out of...
Usual bullet diameter is .312-.313, but I don't know what the bore dimensions are for a .310 Cadet.
Beware that 32-20 cases are pretty thin and fragile, easy to buckle if they hit the bottom of die, or hit the expander ball crooked. Excessive crimping also can buckle them. Last thing-Remington and Winchester don't agree on case length, they're about .020 different. I'm not sure which way Starline went on length.