The USA seems to like the cylinder foam, but the English used little foam balls in a mesh.
They are killer flies, been using them for a few years, but like any other fly, we tend to tweak them to suit our needs. We found buy continuing the foam down the back they float better. http://www.rainysflies.com/...White%20Boobie%20Fly
These are great on a sinking line, cause they will start to float up with the leader and when you strip, they dive. Gartside has the Gurgler that is the same principle and the Tadpole I tie is along that theory.
Black and Olive are killer
Some things are better left alone, Even though, some feel they know better.