Hallo Eugen
i am from the south of Germany and I know somebody in my area who has the knowledge to do these rims in the right way let me know if you need help. I wouldn't#t worry about the looks of the paint too much.
But the Campagnolo Rims from that time have the problem of the Magnesium alloy which was produced in a low pressure casting. today after fifty years those rims can have micro cracks and superficial microporosity that can face a threat today with regards to overall strength and stability. I am not a specialist of those rims but that was told to me by more informed people.
I do use my original rims and have no bad feeling at all, I have not heard of a total failure of such Rim but I am sure there will be other opinions about the subject.
As a matter of fact there are two companies in Italy that reproduce the Rims in the same shape and size but of Aluminium that is less likely to suffer the same ageing problems than Magnesium alloys.
hope that helps a little
retards Ulli