[Arran]

You can also buy resistors from Mouser and or Digikey as they have more selection then Just Radios, WJOE Radio has some as well but the selection is limited too. Generally you would want to at least double the Wattage rating on a resistor, especially power resistors, so if you think it will dissipate 5 Watts use a 10 Watt, or 3/4 of a Watt use 2 Watts. The way these Candohms were typically, but not always constructed is that they wound the resistive wire around a insulated form, and then (I think) crimped terminals on top of the wire at various points. In any event they were often custom made for a specific model, or a certain series of models, but off the shelf resistors are usually manufactured in EIA standardized values, so you may have to go to the next value over what the schematic suggests, or wire combinations of resistors, in series, or in parallel, to come up with the same value.
Regards
Arran