I certainly would prefer to be able to stand when playing the arranger in piano mode (which requires using a sustain pedal), because standing creates a much more 'commanding stage presence', and when singing, standing provides 'optimal diaphragmatic support'. Unfortunately, when playing while standing and operating a sustain pedal as well, means dedicating your right foot to the sustain while at the same time having to support your body weight pretty much entirely on the left foot.

So far, the only compromise solution I've found is positioning the keyboard at somewhere 'in between' sitting & standing height and utilizing a fairly high stool to sit on and/or lean against. Not quite as good as standing, but better than sitting. Anybody here have a better solution or suggestion for me? Thanks.