re: calcium - I actually take 2000 mg (500 mg 4x a day) because I have osteoporosis, but 1500 mg (500 mg 3x a day) is pretty standard for RNY patients. Don't forget - we don't absorb everything 100%, which is why we have to do things like take two multivitamins a day, too - whereas most people just take one. So no, 1500 mg is probably not excessive for a WLS patient.
P.S. VSG patients don't have the same malabsorbtion issues that RNY patients do, but I think most of them are told to take 1500 mg a day, too.