I too went to 42s and noticed less fatigue in the shoulders on longer rides. But given I'm over 200 lbs. I doubt there is any aero advantage and thinking about weight savings seems like an exercise in deception to me. Hope you continue to enjoy the new bars.
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A conclusion is the place where you got tired of thinking. - S. Wright
Favorite rides in the stable: Indy Fab CJ Ti - Colnago MXL - S-Works Roubaix - Habanero Team Issue - Jamis Eclipse carbon/831