Well my first surgery in January was for posterior instability. They did a posterior capsular plication.
Every surgeon is different but I was in an immobilizer ER sling for 7 weeks, started physio at 2 weeks post op, and went twice a week. I was not able to do anything with my horses until end of June when we decided that I needed another surgery so I could go ahead and ride as he was going back in there. I am now 3.5 weeks out from the second surgery and doubt that I will be sitting on a horse until January. I am not asking and will go with what my physio says. I was not allowed to clean any stalls until the end of June either and it was then 1/2 a wheelbarrow and no hills at all including the manure pile.
I will say this, I hope you have an easier go of it than I did. This has been the toughest rehab I have ever gone through.
It goes without saying that I hope you have found yourself a shoulder specialist to do the surgery. I will keep my fingers crossed for you that yours is a straight forward simple surgery and a straight forward recovery and rehab. Mine was complicated and has been a long standing problem that they are still not sure they have 100% fixed. I had/have multiple problems with both shoulders so we are all hoping this last round fixed that shoulder but time will tell.
Find yourself the best physio for shoulders in your area. I drive over an hour to see my guy but he is renowned for his shoulder rehab, that his all he does and I was sent to him after failing to get anywhere with two other physios.