It looks to me as if the cream already is the stop border. I would think you need to audition the border using that as part of it.
As for me, I think I would take off the white, put the darkest as the first stop border, add the squares on point, then perhaps another small dark to match the first, and then a large border of the print that matches the inside.
Another way would be to make the white you already have on there very narrow, to look like piping.
There are so many ways to do this. It is soooo pretty, you will find something you will like.