I tried a couple of different slings during my broken shoulder/trainer workout phase. Most slings are too big/cumbersome and you don't want to sweat in them.

Ultimately the best thing was just something simple around the waist that the arm could be tied to to restrain it. As I got stronger, I would allow my hand to be free and only restrain the elbow to the side so I would use my hand to balance for standing.

something like these:

http://www.braceshop.com/productcart...zer-51p585.htm

http://supports4less.com/birdcronin/...mmobilizer.htm

http://supports4less.com/procare/del...mmobilizer.htm

The key is having the elbow fixed at your side nice and tight. I can't imagine wearing something like that for an hour or 2 a day will make that much difference to your doc.