I was a big pot head years ago. It wasn't until the past month, and over 15 mos. post op, that I decided to start smoking again. This is my experience.
I do not have munchies like I remember having before surgery. Plus, I feel more constriction with the band after I smoke (to the point where it is difficult to get much of anything down). My advice would be to wait to smoke until you have a good constriction with your band, which can take months. Plus, with time, you would have developed good eating and exercising routines. I am still losing weight since smoking mj.
I was "miserable" the first 9 months post-op. My weight loss was slow, and I had no energy. But once I got to my proper "fill", the weight melted away and my energy levels soared. Personally, I think if I were smoking mj during those 9 months, I would have been more miserable and possibly sabatoged my weight loss. But everyone is different.