sorry, couldnt help myself. i dont think its going to be critical for a cab. not for the controls and wotnot. anything will work.
the main thing to consider is that if you are going to be using crimp terminals, will they crimp on the wire nicely (not too loose, but with ALL the strands of the wire able to fit in). if you are soldering, then it really isnt critical. i used cat5 cable which is about the size of telephone wire, only stranded.