No advice on the borders but I love the setting of this gorgeous quilt. Very unique.
On second thoughts how about a 1 inch yellow and a dark blue for the final border, but not too dark that it will overwhelm it.
I keep scrolling back up to have a look to see what colours jump out at me.
You have purples and pinks but I don't think they will work
Scrolled back up again, definitely not green
Back again, top left hand corner block, is that a medium blue in the background, I like that colour
Scrolled back and I really like that medium blue (if it is blue)
Will get off the soap box now, just remember you did ask