How to change avatar column width?

[needaltuna]

This is a question that's been asked before, but no one has provided an answer. I need to decrease the size of the left-hand column in posts that displays avatars, usernames, and post counts. Specifically, I need to decrease the amount of space on the right side of the avatar, which, for some reason, is always greater than the amount of space on the left. Is this achievable?

Thanks.