Any particular reason for using a downward sloping stem?
Given that you have a relatively small amount of seatpost showing, it kind of looks as if you would be better with a frame one size smaller and a stem at the normal angle?
Wanted a traditional look, that means horizontal top tube, horizontal stem. My stem might be tilted about 0.1 to 0.3 degrees down from perfectly horizontal as a result of the headtube being slightly steeper than exactly 73 degrees. A -16 degree stem would actually be perfect for this build but this is the closest in the 3T I could get. I like that some manufacturers like 3T are starting to make the -17 stems again.
A smaller frame in colnago means just that, a smaller frame. That generally means shorter stays, front center, and wheelbase. I am perfectly balanced on this size Colnago. That's one of the best things about Colnagos to this day... you can still get frames in incremental sizes of 1cm and find a perfect balance. I've ridden one size smaller and I've ridden one size bigger. This is the one for me.