Jim, Are they spade connectors? If so, you can just put both spades for each channel under the same binding post. It shouldn't be any problem at all.
3 responses Add your response
No problem at all using both connectors on a single speaker binding post, as long as it can be done in a physically secure manner, and as long as you make sure that + and - don't come in contact with each other. Sonically it might even produce better results than using just one wire, in part because resistance and inductance would be lower than if you used just one of the wires for each polarity.
Taping would work ok too, albeit with sonic results that MIGHT not be quite as good. Although personally I would be hesitant to do that because thoroughly removing the tape residue, if necessary at some point in the future, might present a bit of difficulty.