Very nice workshop. I have been shopping around at vintage Ferrari's and thought it might be fun to do some work on them myself and thought of building something similar (although not quite as nice). I just never have time anymore to do fun projects. I barely have time to get my cars to my mechanic anymore.

A good rule of thumb. If its fluid replace it. I would also go ahead and get all the filters on the car after a test so that the old filters pick up any "crud" that might have been floating around in the associated system.

A friend of mine collects Rolls Royce cars and seems to have the same problem you do. Keeping the batteries charged and keeping them "running" when he wants to drive them (Carburators are evil when they sit). Have you considered hiring someone to do this for you? Someone with some mechanical abilities that can come out once every few weeks and drive the cars to keep them going? Might end up cheaper in the long run and its much better for the car.