Ian, do you think that your perception of the Bose sound - Mono vs Stereo - has anything to do with the fact that (I believe) you play mainly instrumentals (no vocals) and by yourself (solo, with no other musical partners or live instruments) and thus have focussed on Effects and Sounds that rely quite heavily on Stereo panning?

If that's the case, and correct me if I'm wrong here (I frequently am) than perhaps that's why you feel, for you, that a single Bose is only adequate for your needs, and is the reason you set up and prefer your show in Stereo?

This is a serious question/observation, and I'm not judging you in any way.