I don't know if macros can be mapped to controllers, but this might help.

/macroicon "Gnashing Fang"
/ac "Wicked Talon"
/ac "Savage Claw"
/ac "Gnashing Fang"
/ac "Burst Strike"

I'm not 70 yet on my Gunbreaker, but I'll test if the Continuation combo can be crammed into there as well so all I have to do is just mash that one button until my keyboard breaks.