Good luck, Deane...I had to go to lighter gear a few years ago, after abdominal surgeries...the S910 was no problem, and the S950 is only a tad heavier, and should be okay, as will the PA-600.
All the best in your recovery.
Ian
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Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.