Sorry to hear you're leaving GT - especially because I have the same problem of arthritic hands. And I'm the same age as you. Have you investigated different (and easier) voicings of the chords you usually play - often you can play simpler and nice-sounding alternatives. Mr Schlegel on GT is an expert on this sort of thing so maybe he could point you towards relevant lessons. Just that it seems a shame to give up, I know it's a day I dread myself.
Best wishes, Steve