I would go larger if you are set on two pendants, otherwise they'll look tiny over the island. One way to to test the look is to make paper cutouts of different sizes and test them over where your island will be. Restoration Hardware's Benson pendants are similar, and Kichler Lighting makes versions as well. Here is a link to your pendants: VC Yoke Pendants

If you like the large look you can consider a chandelier over the kitchen island, take a look at the projects bellow. We make unique lighting made of art blown glass in beautiful styles, we specialize in custom lighting and can design the chandelier in any length. If you would like to receive our catalog by email contact Sales@GalileeLighting.com visit www.GalileeLighting.com We offer free design consultation you can call 305-807-8711

Too small for what? Is that your island? I think they look nice and I would not go any larger.

If your drawing is to scale, then proportions look great.