Well, floating higher is for the fisher, not the fish. There is an article I read recently in a fly magazine (can't remember which one) that you might not want your fly to ride right on top. That in truth, there are very few bugs that do.
I know I have cast out a nice dry before all Frog Fanny coated and it is beautiful sitting there and very visible, but the minute I give a slight tug and it goes sub surface, that is when the hit.
Some things are better left alone, Even though, some feel they know better.