Easy assist macro/hotkey:
/xtar 13
/assist
Works for dps - put MA on ETW in slot 13
Works for healing - put boss mob in slot 13
/assist main
Will target the main assist's target. Downside, of course, is it doesn't work if there's no main assist set, and I have no idea what it does when there's two main assists.
I have xtar1 and xtar2 set up as raid assist 1 and raid assist 2. Then my assist key is simply xtar1 or xtar 2 (for events like Droga)
/xtar1 set raidassist1target
/xtar2 set raidassist2target
Hotkey
/xtar1