Jolly1, Thanks for the background stories. Now we know more about you and we can offer suggestions or answer your questions accordingly. Similar story here on how I got involved climbing trees (I needed to clean my trees), similar age 54 and Arthritis sufferer for 15 years myself, Climbing plus my Dr's treatment has it completely under control now. (In remission now.)
I have a relative in Nashua, NH so I may visit you one of these days when I go there in the warmer season. (I live in TX. That is like a whole other country!)

Nice selection of gear and Saddle from New Tribe. Peter's video is VERY good to perfect your climbing and to learn the basics. Probably better than the local arborist who sees you as potential competitor (not likely) but that is the way they think.

Sounds like you are at the point of rapid learning and improvement which will get better with more climbs and trying new ideas, confidence with tying knots, making transfers, redirects, etc. A lot of that is presented in the Tree Climbers Companion. Review Peter's Techniques a few times and your confidence will continue to grow. If you have a chance to meet other Recreational climbers ( Moss is near you in Boston and he is a great climber with lots of climbs taking place there. Hope to be able to meet you personally one of these days.
Make sure you inspect your trees carefully before climbing. We apparently do not impress enough that part to the new (and old) climbers alike. :_b_link__:

Climb Safe and stay Low and Slow at the start.