Progress by the (im)patient:
Rode a bike (upright old English Phillips, wouldn't dream of doing dropped handlebars yet) a couple of blocks sans sling. But it puts shoulder at the limit of ROM to reach the right handlebar, brake, and shift, so no margin for anything unexpected and risk of tearing up surgeon's good work if fall that way, so will put this concept on the shelf for a while. Sure do miss it, though.
But, more successful: Jogged a mile with sling cinched up fairly tight, dog joined me and liked it and I didn't dislike it. I have missed running. But I need the shoulder movement for it to be a balanced gait, so this will be a short-distance thing for now, probably not to exceed two miles lest my body compensate with some kind of bad habit.
But it's getting better and working it does not increase pain. Seeing the doc next Tuesday.