He he...U already have how many sub1500 sets and want a sub 1400 to improve climbing lol.
Purchasing a 1300g wheelset to improve climbing is like purchasing a 45mm profile for it's aerodynamics.

A sub 700g could may be noticeable, but hardly, but by all means. I hear you. Image is everything. Obey your image.

Building something with the XR 200 rim won't even lighten your wallet much. I pressume you builder is a forum guy
giving you a forum deal. He pays $10 for the rim (yup!) quite a bit for the hubs. He could go for the Sun hubs (once
designed by Tune) and get a decent price (and quality)

You would then have a cheap sub 1350 set of wheels, but the Shimano would be better. Sorry to break that to U