I bought one as an experiment for one of my putters. They're very nobbly, so you can definitely feel them, but the nobbles obviously reduce the surface area contact, which would concern me on a full swing.
I don't have arthritis but a nerve problem that sometimes causes numbness and/or pain in my hands. When I'm having a flare up I find that midsize grips and a glove on both hands gives me the best feeling of control. A friendly pro shop should let you spend 15 minutes having a swing with a variety of grips.