I looked on tractor data and it list a Massey Ferguson model 261 as a class 11/1 3 point setup. I am not familiar with a multi class arrangement- what does this mean?
It says Class II/I. So it's a Class 2/1 hitch, meaning that lower arms can go narrow enough for the class 1 implements and wide enough for the class 2. It may also have lower link balls with holes for cat 1 and cat 2, although it's not really necessary as bushings can be used to go from 2 to 1.
PTO class? I've not heard that term before. PTO is normally specified by power - the HP delivered and the RPM. Then they can be transmission driven, "Live", or Fully Independent.