Are you trying to avoid even the last unnecessary gram on your bike? Why not save some weight on your spacers? Racy carbon style included.

The Vertic Carbon Spacer Set is made from high-quality DU Carbon and includes two 10 mm and one 5 mm carbon spacer with an outer diameter of 34 mm to fine tune the height of your race bike’s cockpit.
 
(Stem Spacers set)