This poll suggests Hillary's lead is around 5% nationally.
I'm always uncomfortable extrapolating a single state poll to a national poll, especially since we have plenty of national polls, but...I'm curious on how you landed at Clinton +5. That's not a hard swing versus 2012, unless you allocated undecideds/third parties and then applied a national swing. I think we should be very careful about applying hard swings vs. 2012, even in states that are demographically representative of the U.S., and Montana is
not demographically representative of the U.S. in any sense.
edit: and just to emphasize, I agree with Bundou. Extrapolating a national lead from a state poll, especially a Montana poll, is a really, really bad idea