Please don't stipple over all those beautiful flowers!!! Echo them, maybe more than once, inside perhaps also as well as outside the petals. Stay with the theme (not with current trend). I think the idea of a small flower motif on the border sounds nice. You might try laying threads (background and petal colors and.....?) around the flowers and see what looks best before trying it out in reality. It is a beautiful quilt and it deserves to have it's integrity intack. So, that's my opinion.