You sound like a man who needs a
ketch.
Turning a schooner into a cutter would be really hard and you're left with a huge
mainsail and headsail. Why not a
ketch? This keeps the sails small and allows the wonderfully balanced
jib and jigger when the
wind gets up. And downwind a mizzen staysail that doesn't require a trip to the foredeck to set like a cruising chute.
Given your physical issues, I'd also keep the sail area on the small side.
Set her up so you don't have to think about reducing sail until 20 knots. At that point take down the main and be good to 30+. Sure, you'll run the
engine in winds under 10 knots but most people do anyways.
That said, moving masts is likely to have serious structural challenges. Both for the downward force of the mast and the upward pull of the shrouds. You'll need a good
marine architect.