Personally, I found it easier to have my 5 core tanking abilities clicked during fights, since im not using my mouse for anything else. I have a seperate button (G3) which does my boss-dps macro (pops trinkets, efficient FS management etc) but buttons 1-4 on the slave accounts use a lesser dps macro for trash.

Works okay so far.. but I'd like another row of G keys to use.