After looking at the painting for a while, I decided that the daffodil bouquet needed some filler. I clipped some sprigs of nandina from the front of the house and stuck them in the arrangement. (I find that nandina and grape ivy are wonderful still life fillers.) The neck of the blue vase was so narrow that I couldn't splay the daffodils any better than you see them here.
I'm still bothered by the daffodil stems that transect the blue vase, so I'll have to work at that. I think some strategically placed nandina will soften the lines.