Jerry Martin – Thanks for the clear explanation and helpful video. Usually some piston changes need to be quicker than others, so as X-keys are small and have very little travel, it would seem sensible to reserve them for changes when one has a bit more time to think. What your video brings out is that a strip of them will fit into very small spaces, which seems a fair trade-off for having to aim accurately.
I’d not heard C S Lang’s sonata before – it sounds an interesting work, though potentially complicated to play. If you like British organ music, are you aware of the organ works of John Ireland? They vary considerably in difficulty, and unfortunately some of the more interesting pieces are beyond me technically, though you might well manage them. Plenty of examples to listen to on youtube, and they’re all published in one volume by Novello e.g.
https://www.ebay.co.uk/itm/144555081774 ... =137596852I must admit I love Ireland's music, and consider him under-rated; three of my advanced piano pupils have learnt some of his pieces and very much enjoyed them - so please excuse the plug!
magnaton – If I decide on Plan B – an auxiliary device beside the bottom manual – I should certainly consider Launchpads. Are they reasonably quiet?