F4, Taylors are indeed nice guitars; I've only played a couple, and they were strung with fairly heavy gauge strings. Going to lighter gauge strings could make it easier to play, but you'd need to pay attention to neck relief and would probably need to "relax" the truss rod somewhat to compensate for the decreased string pull.
I started getting the same problem with arthritis, so a couple years ago I started taking one of the "joint juice" supplements (Chondroitin, glucosamine) - I take one morning and night. It's made enough of a difference that I don't notice the problem unless I focus on it - might be the placebo effect, but as long as it works for ME I really don't care WHY
These
Are the strings I've been using on the steel string acoustics - they seem to be slightly less volume than heavier strings, but these days I'm playing for ME, and I don't care. If necessary I can put the battery back in and run it thru the studio speakers.
The lighter strings DEFINITELY lessen playing effort... Steve
I don't know how far your arthritis has progressed, mine wasn't horrible when I started the joint juice but IIRC, it took a few months before I noticed ( or realized) the difference...