I think you're taking a risk with a short cage RD with this setup. IIRC, when Campag introduced the 13/29 "climbing cassette" - a relative dinnerplate at the time (late 90's I think), they also introduced medium cage RDs, which had the clearance for the 29t sprocket and the necessary chain wrap capacity (30t) for the 13/29 in combination with a 39/53 crankset. Short cage RDs have a chain wrap capacity of 27t, with a little fudging either way, but I think 30t might be too much. There's a useful discussion about this on the Branford Bikes website (my "go-to" for Campag parts and service)