I think I'd stick to the larger border as well. That said, since you don't have enough of the red to do the wider border, what about a combination of either the red/cream or the red/black to make up your 6.5" border and then bind in the red? Put the opposite color on the outside so that your binding stands out? Most times I like my bindings to either 'stand out' or tie in an under-used color in the body of the quilt so it ties everything together. That's just me, tho.