Ideally they would be the same wire as the speaker wire. I sometime do on on the top and one on the bottom honestly not a big difference.
HOW CRITICAL ARE JUMPER CABLES
When using jumper cables instead of biwire speaker cables, do the jumpers need to be as good a quality or better than the actual quality of the speaker wires? The jumpers need to be 6” to 9” long. Also is it better to hook the main speaker wires to the low end and then run the jumpers to the high end or visa versa?