Hi Ranchomirage,
I just purchased some MC2301's and was faced with the exact same dilemma as you. My previous amps, Octave MRE130 had two pairs of speaker out for each mono amp and I was able to use two pairs of double shot guns, ala biwire to the B&W Nautilus 800's. Now, facing the same issue as you, I also did exactly the same thing, running the mid-highs to the 4 ohm taps and the bass to the 8 ohm taps, sounds great to me. I thought about swapping, but based on your experience, I think I will stick with the current configuration.
On audioaficionado there are lengthy discussions regarding bi-wiring macs and many more enthusiasts there than here or asylum.
Glad you are enjoying your new macs. I am in music heaven with mine.
Ciao,
Audioquest4life