I lucked into a 64 cm Master Olympic on Ebay, and having arrived I am now in the process of building it out.

It has a 27.2 seat tube, but because of the "pinched" design my former seatpost isn't getting in far enough. Do I need to consider an extra short post or is there a specific Colnago post that lines up with the shape of the tube?

Thanks in advance

I called my local dealer and he said take a hacksaw to the seatpost. Did it, buffed up the edge with a dremel, and am in business.

I use a Chorus Ti post in mine. It's exactly the right length, but of course you can use just about anything an cut it back.