Jim - I invented constipation!
At it's worse, Miralax was the solution for me. I'd been down the road of Benefiber, Psyllium, Senna and countless other things.
Milk of Magnesia was the first thing the doc suggested and that was at just over a week out of WLS. That worked well too.
Fortunately, I'm pretty much weaned off of most things. I still take 2tsp of Benefiber a day but that combined with Sunsweet prunes has gotten me back on track. I'm taking a good dose of iron at the moment because of a low count at my 6 month check-up. So far, I'm not having a problem.