Auditioning borders

I finished piecing the "back" of Otto's quilt (which is now really the front). Somehow I was off in my measurements in a couple places and so in the spirit of this quilt, I simply whacked some edges. It took me a few days to get up the courage, but in the end I think it's ok. I had planned on red borders, but I don't have enough red fabric and I can't get more. My first thought was yellow -- bright and cheery, and there's yellow in the blocks. But when I tried it, I wasn't too crazy about it. It just looks stuck on.
I neglected to add the red inner border and red binding when I took the yellow border photo (they are on the right side in the photo below), but I think it needs an inner border.
My memory was that this fabric was white with black squiggles, but it's just the opposite. I think I prefer it to the yellow, but I know the quilt shop has the white with black fabric, and I think I'd prefer that to either of these -- it would be brighter than this one, and fit the design on the quilt better than the yellow. Right now the top is just lying on the fabric, but I think I'd have the stripes going the long way across the top and bottom, just like they are now on the sides. The side borders will be bigger than the top and bottom ones.

Any thoughts? All help greatly appreciated!