I have a 2021 Ultra that was converted to a trike. I changed my tire at 10K - and still have 4/32 left - which is a lot. I could have probably gone another 10K miles.
The reason I changed is because I wanted to install the Avon Trike tire. This tire has more middle thread and is also a radial. In my earlier trike days, we use to run a rear tire backwards - does essentially the same thing.
I see you are in Waterford - so not too far from me. I spend a bit of time at Arsenal - perhaps we have run across each other?
Have you considered - or have you joined the local HOG chapter. Great group of folks. Why not come out and ride with us
Don