I like the red much better!

If this were mine, I too would use a gray for the cornerstones. I'd use colors already there, pulling the blues and the grays out. I'd do a narrow border of the gray all the way around, and then the rust, then finish with binding in the black.

I think your duck panels are rather a hard colouring to deal with. You did a terrific job. I really like it. Congratulations.

love what you decided on!

My choice would be for a gray, pale to enhance the main panels by drawing the eye to that area. Just a thought.

Love your choice of rust, just perfect!

I'm different than most as I prefer the lighter cornerstones. I feel like they connect the blocks and keep them from being totally overshadowed by the very dark sashings.
If you don't have the gold that is the center color of your sashings for cornerstones, perhaps picking up the color of some of the foliage... the golds I think would tie it all together.
My first vote would be for the center color of your sashings tho.

Lol, I see I was missing reading all the posts and I love your final choice, since it echoes my suggestion! LOL... well done, it looks great!

I think your final choices are wonderful! The rust caps things off nicely, without taking away from the panels. The recipient will love it; that is such a thoughtful gift, and I am sure it will be greatly appreciated.

This is a beautiful and calming quilt! I think the blue squares go nicely with the peaceful nature pictures.