I used those oil ports on a set of Campy Tipo low flange hubs for years. Just added a drop or two each port each ride, and aside from having a little oil and dust collected on the spokes after riding it worked great. I probably lubed them that way for ten years, replacing the balls during each spring overhaul. They were new in 1972, and are still ridden on occasion, now packed with Park grease. Races look nearly new!
Mike Hall
Davison, Michigan