American artists seem to favor flat bristle brushes for watercolor, a preference which I've never quite understood. I am a fan of fat round brushes that can hold a lot of water. This artist is using a round brush and I think it's working great...
Watercolor Painting Demo by Ng Woon Lam NWS, http://www.lifineart.com Singapore Watercolour Society and Singapore Art Society member artist. Many Watercolor Juried Shows Awards Winners. 140th AWS American Watercolor Society Show participant