The average replacement dose is around 100-200mcg  (I think) and once they have you on the right daily dose for you, your body will not make aldosterone so you should not have any problems with kidney stones.  Aldosterone is like cortisol--the pituitary only calls for more when it senses a lack.  If you take a good enough dose, that is neither too much or too little, it should see you right really.  There should be no side effects except for initially when you are taking 100-200mg and also your body is making the stuff at the very beginning.  This would or should settle though after a time.