A/B-ing speakers of different impedances.

Quick little video on how to connect and disconnect speakers!
https://m.youtube.com/watch?v=D-g-MPzpQqc

Excellent video. Before YouTube and videos like this only the most advanced and experienced audiophiles knew to twist the wires.

dont think the switchbox will work as you hope as it can’t switch to the correct amp taps for each speaker for you...

Only speaking for myself, but I have found that the difference between the various amp taps to be less than I would have expected.

Use the low impedance tap as your best overall, but since speakers have pretty broad differences in sensitivity I wonder if this kind of A/B testing is that useful to you?

I mean, listening to one pair for 30 minutes, then switching, and listening to the other after a break is not a bad thing here.  If this doesn't reveal to you what you want to know for your long term enjoyment I don't think fast switching will either.