My understanding is that "presence speakers" are those placed between the mains and the surrounds in a 9.1 system. I don't think this kind of implementation is very widespread because not many processors support it.
It seems like going to 7.1 by using the Musical Fidelity speakers (or QS8's) in the REAR would be a more logical next step.
I would think that - since they are part of widening the front sound stage, matching the presence speakers to the mains would be fairly important. But I have no experience in this area. If I were going to 9.1, I'd probably opt for M2's as the presence speakers.
Just use your ears to decide if you like it or not.
