Are you sure you did not "kink" the supply lines between the valve and the faucet? "Drywall dust" would have been flushed out IMMEDIATELY when the water was turned on. If the aerator was plugged, you would get the same amount of water from both sides. Were these the type of valve which you screwed on to the original valves between the valve and supply line? If so, THAT may be where the obstruction is. Ihave a fairly low opinion of that type of valve.