Sorry, Goran, but I believe that "finding the buttons" is a mental, rather than a physical effort.

I agree that "pumping air" and "pressing buttons" are two necessary physical activities, but so is a third: supporting the weight of the instrument.

A well made and properly set up concertina should have a balance between the button spring pressure, the bellows action and the weight, be it an 81 button Maccann, a 20 key anglo or anything in between.

Adding as many straps and fittings as you like to achieve some sort of ergonomic Nirvana may help to achieve this, but in the end it all comes down to balance, and using whatever strength we have to match the well thought out designs of the master makers.

Have we been here before, or was that in another forum?