I wanted to thank everyone for their suggestions on the overflow canister. It appears however, from the responses I got, that I was overfilling the radiator. I've been topping it off just like I do in my newer car. The radiator was just flushed a few months ago, but I usually reserve only the best warmest days to drive my Imperial to work, so it appears I am overfilling it with antifreeze.
As far as the textured vinyl roof on my car, I feel it is one of it's true rarities, and was also one of the things I liked most about the car. Someone on the list said they did this texturing back in 1959, and I am pretty sure that is very accurate, since there is no evidence that previous owners made any attempt to customize the car. After repainting the landau section the roof looks brand new, and very much like a vinyl roof. When I bought the car, I had thoughts about putting stainless steel on the front section of the roof, and making it silver crested, but decided against it, feeling the car would become to much a hodge podge of textures. I love it just the way it is! Bill '59 Crown