Your quilting so far is very geometric and not fluid and organic like feathers. I would most definitely not put feathers in the border. If this were mine I would treat all 3 strips like a single border unit. In fact I would be sorely tempted to turn the design you used in the setting triangles into squares on point and continue the exact same quilting you have done in those down into the border. Sorry for the bad computer drawing skills but something like this:
[ATTACH=CONFIG]609767[/ATTACH]

I agree with Feline Fanatic!

Me too, I like what Feline Fanatic suggests. I know when I like something but to come up with the design is elusive for me. Good luck with what you decide. I'm sure it will be wonderful. Love what you have done. (would not do feathers).

I
like Feline Fanatic’s idea too! And would love to see the finished product whatever you decide.

Watson, what I'm seeing is so gorgeous! I love that shade of blue.
Since I'm absolutely no expert on your question I need to pass but couldn't pass on the beauty of this quilt!
Can't wait to see it finished.