I’ve been looking for a way to make tmux match Powerline :)
The method of copying the tmux buffer to the mac pasteboard doesn’t work for me. I use this hack (ugly, but it works):
bind y run 'ssh localhost "source ~/.bash_profile; tmux saveb - | pbcopy"'
EDIT: The method from the article does work; I just had to explicitly :source-file the change in my .tmux.conf. Turns out the config settings are retained by the tmux server, not the clients.