Do you have any leftover scraps of the fabrics from the quilt? If so, I would make a small practice quilt sandwich and give the beige you like a try. It could be pretty small to just get the idea of how it would look. You could just piece some of the scraps together, just strip piece the together since it's the colors that matter and not the pattern. Then quilt over the fabrics using the FMQ and colors you plan. I sometimes do this to get a good feel for how the thread will look sewed on the fabric, plus, it's a little bit of extra FMQ practice too!