This may sound simplistic, but a proper fitting focused on the shorter reach side will do a lot to quell the issue.
I believe the stress which surfaces is from the shorter side "reaching" for the bar.
Basically, a slightly shorter stem may be all is takes.
From your post is appears that you are ride all around on your bars. A second simple trick, especially if you like to ride on the hoods is to move the brake lever on the "shorter side" up on the arc of the bar a bit, and if needed move the longer side down a bit. The offset should be minimal both mechanically and visually based on your 1/4" differential.