Well, if you put in too much, it will just squish out when you tighten the cones. Start with everything clean - inside of hub, cones, bearings. I squirt with WD-40 and wipe clean. Then put a thin layer of grease inside the hub (1/16-1/8 inch thick) where the bearings will ride. Rub grease on each ball bearing before you put it in. When all the bearings are in, you can dab a bit more grease on the rows of bearings to fill the space between them. Then put a thin layer on the bearing surface of the cones and re-assemble. I try to err on the side of being liberal with the grease, but if much squished out when you tighten things up, you're wasting grease.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72