A twin size batting is 72 X 90. That may influence your decision.

I say do a black border or a white border and the bind with the stripe fabric.

I think they look great as they are-just add the binding Love the colors

Either way it's beautiful! My personal opinion though would be to just bind it as is in black so the striped squares will pop. Can't wait to see it finished!!!

I'm going to be different, IMHO, if it was mine. I probably would border with a 1 inch black, then add a 2nd border with a bright color. My binding would probably be black or one of the other bright colors in the quilt.