I'm declaring my quilt a success.
Mereth suggested making these joins in the border, to help blend the fabrics into each other, and it worked really well.
I put the very dark green/blue in opposite corners to balance the border, and I really like how that looks in the finished top. I wasn't going to have a narrow inner border, but there were 4 strips of dark blue left over from the jellyroll; I cut them in half, so I had enough inch and a quarter strips for a very narrow border. I like how it separates the border from the centre, it's only a small pop of deep blue but it really adds to the overall effect.