Campagnolo hubs are smooth becase the components are precision. The axel has nicely cut threads that are concentric radial and axial. The cones are bored and threaded the same, with the bearing surfaces precision ground and lapped.
The race inserts and the hub all precision fit and aligned, very nice. but cost more to produce.
Here is how they fail, if you adjust the bearings to no play but smooth when you turn them, they will load when the skewres are tightend.
Metal is elastic like rubber, just harder. The skewers will actually compress the axel and bind or load the bearings causing the cones or races to pit or have metal torn away and the balls to get flat spots ect.
Check it out for yourself this way. Adjust a bare hub to zero play, install it on a frame and check the increased drag.
So this means, a slight amount of shake or play should be left in the cone adjustment so when the skewers are tightend and the axel is compressed the bearings will not be over loaded.
How much play depends on how tight you clamp the skewers.
Lubrication, Well, I have seen many use off the shelf products like Lubriplate or automotive grease. Campagnolo at one time anyway, sold a reasonable quality grease.
When I was racing I used oil, Mobil Velocite medium spindle oil. Not practical for general riding however.
What I use now is Exxon Andock Precision filtered spindle bearing grease. This grease is made for angular contact bearings simular to cone bearing bike hubs but for precision machine tool spindles. Cost is about $90 for 50cc syringe.
The bearings will last more than a life time if the bearing preload and lubrication is controlled.
Don