CM10's and Mcintosh MA8000

[Jagman]

Ok so I'm really struggling right now with my setup as it relates to the 8 or 4 Ohm tap on the MA8000. My prior system of 15 years was a Classe CA301 with Hales Transcedence 8's. It didn't have separate taps for various ohm rated speakers, so I never really had any decisions to make....it just sounded great all the time.
I've had the Mac and CM10's since January of this year. They were initially connectd to the 4 Ohm taps and I liked the sound a lot, even though I felt the sound was a little warmer and with less punch at times than was ideal.
I switched to the 8 Ohm taps and heard an immediate difference. More punch, crisper highs, perhaps a bit lower volume bass, but tighter at the same time, more dynamic and more detailed. It also plays quite a lot louder at the same volume selection. The only issue here is that at times the highs and vocals sound overly bright and I sense greater listening fatigue.

So I find myself switching back and forth way too often and can't seem to land on one or the other. I think the 8Ohm tap gets more from these speakers, just that listening is easier at times on 4 Ohms, but I know they aren't as revealing.

What have Mac/B&W users settled on for the most part? Anyone experienced the same level of confusion or inability to decide? Can anyone relate?