Brake size/interchange

Wondering which measurement to use to determine brake size, the drum width or the shoe width. Rears have a 2.5" drum width and a 2" shoe width. Fronts have a 3" drum width and a 2.75" shoe width. 11" drum diameter all round. Need to order some parts and want to be sure.

Part 2 to this is will all the brake components bolt up from the current 8.25 rear to a 8.75 or 9.25 rear?

Thanks