dosing for mk677 is usually either 25mg per day or 12.5. Helps with sleep and some people say it makes their joints feel better. Just beware it can elevate your blood sugar. I wouldn't take it if you're already carrying some fat, as you'll already not be very insulin sensitive to begin with.
Overall, I think the idea of this stack to get back quicker after surgery is a bad idea. You need to let the body's healing process play out. Getting strong too quick is just going to risk more injury. Muscles can gain strength quick but joints can get overwhelmed quick and bone density doesn't improve at the same rate strength can with the addition of "help." I'd shelf the stack and exercise some patience.
I'm three months post surgery, bones have healed, trying to "align the muscle fibers (best way I can describe it), the harder I work for the next three month the more benefits I will see down the road (or so I'm told)...
Hard to get info from the doctor (they always tell you to play it safe), there is info on the net from other bodybuilders (some who have had more aggressive doctors and physical therapists to push them).
The bodybuilders that have had the same surgery talk about there training, but I can not find anything on what chems they have used (probably steroids), although based on what you and others have said, that could be detrimental if the body isn't ready.
I'm doing light weight training, 12-15 reps...many, many sets.