My panel started out about that size. I trimmed off more on the sides of the panel than the top and bottom (the green/blue) and then added a wider first border top and bottom. I don't recall the exact measure the quilt ended up, but it's sitting on top of a king size bed in that picture.
This is an other idea of surrounding the panel that does not have dimensions that work well with the desired finished size. This one started out with a paper pieced center.
