Unless you are going to be under noise regulations you really dont need to go with a stict pattern prop. Go with the prop that works best on your setup. I asked this question several months ago in the pattern forum and that is the answer I got.

The high pitch is not for speed like bla bla said. The newer style pattern plane designs are proof of that... the newer planes are not built with speed in mind.

I have a 90 sized pattern plane and use the old standby 14X6 prop.