Something none of you have mentioned is testing the CA hinges after they have been installed. I give each hinge a strong pull to see if any separation is detected. If so, I drill a pin hole through the hinge but not all the way through to the top. This hole goes through the underside of L.E. of the control suface and T.E. of the fixed surface and put a tooth pick in the hole to further secure the hinge in place. This way, I only need to touch up the bottom where the pin goes in. I also agree that drilling a hole into the slot allows the CA to "wick in better".