Finally it turned out that the alloy wheels from Image, which are excellent wheels and the service and knowledge of Harry is great, need a centre adapter for my Rudge hubs. At the end the wheels would have a 10Kg weight including the adapter. This is the value what I already have with the recent Minilites and therefore I don't need to spend money for a change.
Perhaps I can find sometime other Minilites, 6,5J instead of 7J to free the space to the suspension, keeping the offset, perhaps made from magnesium and combine them with the current adapters.
I thought about a change to 5stud hubs, but that is too much an effort and the Rudge hubs itself benefit from lower weight.
I currently enjoy the car as is. Sometimes the urgency of projects is relativated after a first push...