OMG, you ladies are doing fantastic!! Your rounds look beautiful and they fit like they're suppose too! Phew, maybe I picked a border that was right. You're going to be so surprised at how your quilts turn out, think you will love them!!
Mom-6 think I would put your block on center now if it were mine. Maybe even with your team fabric and then the next round go with your solid colors. If you wait until the very end, they will be huge triangles that you have to put on to square it up, lots of fabric with no movement. Think you would be happier with it on now and remember you don't have to go with a 6/12" border next time if a 4 1/2" will look better. Not a set rule here, you could put on 4 1/2 or 6 1/2 every border if you want.