Were it my dilemna, i would use the Campagnolo components on an Italian frame that fits you. Colnago's can be awesome, but there are so many other nice and colorful frames, - Gios, Cioss, Rossin, Guerciotti, - we could go on and on
I would assume tubing grade would be the chief difference between an rb1 and a 3. There may be other differences, but probably nothing major--- i thought they were all made of nice Ishiwata tubesets but could be like the difference between Tange 1 and Tange 2

A nice Bridgestone, being a Japanese classic, would look best built with either a Suntour Superbe parts kit, or a Shimano 600 kit-- in my opinion (if its your bike though, your opinion is more important)