Only warning I have for you is, suggesting to add either "harm" to all of your macros... i.e.

/cast [harm,nodead] <spell>

OR Add this to the top of each of your macros:

/assist <name>
/stopmacro [noharm]



What I'm concerned about is if you accidentally end up pulling an add that you didn't intend because your secondary either wasn't supposed to assist but tab'ed a mob and started attacking. Since it sounds like you're only 2-boxing, adding /assist <name> to the top of each button seems like it would work.