I shoot both recurve and compound. I have never tried using a release with my recurve. But, being that you have arthritis I can understand why you're going this route.
When I shoot my compound bow with a release, I have a kisser button on the string that touches the corner of my mouth when I pull back & aim. Maybe this is an alternative to your middle finger at the corner of your mouth. Just a thought (again, I never had to use a release on a recurve bow.)
I also use a nok-set so my release gets mounted in the same spot ever time. Some guys use a "D" loop on their string(compound bow).