Personally I think the whole bike is a right dog's dinner and you owe it to the Gios legend to let someone with far more taste and better aesthetic awareness take ownership of it - I'll give you a couple of hundred for it
I agree that tan wall won't go with those rims in fact Hilary Stone has a pair for sale that are good for reference:
http://hilarystone.com/images/sale%20im ... o-Blue.jpg
I'd stick with the current ones because for a start the white will dull down with use and then maybe when they're worn out how about blue/black tyres? Assuming you can find some modern ones without massive logos on them.
Just when I think I could splash serious money on a modern carbon bike you pull this one out - what a beauty!