Ideally, if you had an audio version of heavy duty jumpers, similar to non-fused HVAC service disconnects, you could do it that way. It still would not be advisable to change modes it with the amps on, but you would not have to worry about voltage passing through the thing.
Ask far as the sound of anything who can say what's right. A friend of mine bought a bunch of Mark Levinson gear (ML-2s ML-7, plus a pair of Quad 63s) from a guy named Peter McGrath. Michael said that McGrath always said that with any gear, it was a case of choose the distortion you like best. It's the old: Ford or Chevy, Martin or Gibson, etc. I honestly feel that the pursuit of audio perfection can be a very long road with no end. I like to sit and listen every once in a while, so I don't what to let tweaking become an end in itself. I can't remember exactly who, but I think it was Picasso that said that, paintings are never finished, they are merely abandoned.