Rear brake rotor replacement

[Geoman]

I'm in the process of redoing all of the brakes and with the rear ones, the two slotted screws that hold the rotor on had rusted tight to the rotor and I had to drill them out. Would anyone know what size screws those are so I can pick up some replacements?

I also figure that while I have the rotor off I should give some attention to the parking brake shoes. Is there a step-by-step procedure written up somewhere that I can follow? I don't suppose the axle hub, which contains the wheel studs, comes off to provide better access to the parking brake mechanisms?

Thanks all.