Apparently when standing, the load on vertebral disks is approx 125% - when lying down it is approx 85% - but when sitting it is 240%...As I have back issues, I have been seeing Doctors for a long time, and one of these guys imparted this information recently to me quoting some journal or report which I forget the name of now.

Thought it might be of some interest for those reading this thread.

As a former accordion player, and a piano player I am comfortable with both positions.

I think it is as DNJ said, (and I paraphrase) that doing the thing that makes you feel most comfortable when performing is the way to go.

Makes sense really, that if your body is comfortable, your performance will be too.

Cheers
Dennis