I'd check the wiring diagram, as they should show the fusible links in the wiring looms.
If you can't find the info, add all the circuits up on each wire and that's the theoretical maximum of the circuit. However, if the info. is not readily available, I think a 40Amp on each circuit with a view to possibly uprating them if they blow would be satisfactory.
But if it catches fire I didn't tell you that ok! :shock: :twisted: :lol: