Just a follow up to q to my ballcock problem in the water-tank in the first floor bathroom. The plastic water tank is about 2ft vertical, 2 ft deep and 2 1/2 ft horizontal and the inflow (where the ball-cock is affixed) AND the overflow pipe are both about one-and-half inches from the top lip of the tank. Are these the right places to insert the in-flow and over-flow pipes or should one be higher than the other? Obviously the level of the ball-cock is relevant too, but are there also guidlines for where these holes should go too?