Infinity Kappa 7.1 6ohms speakers

I have two Infinity Kappa 7.1 speakers which require a 6 ohms feed. However, my amps only deliver either 4 ohms or 8 ohms.

How does this impact the speakers' performance? Also, which setting would be better for the speakers?
I think the consensus will be to try both the sets of taps, in turn, and see what sounds better to you. Good luck, Dave