I see that all pattern planes run really high pitch props. There is so much talk about constant speed and down line braking that I figured you would need a big diameter low pitch prop. Why is it that no one uses this type of prop?

I ordered a CA Model Epsilon with a OX FX 91 to get started in pattern with. The manufacturer tested it with this setup and an APC 14x8 prop. A few guys complained and said that the .91 wasn't enough when you go over the top of a square loop. I would imagine that a 14x6 turning a few hundred more rpm and putting out a couple more pounds of thrust would resolve this. However the wide open flight speed would be 10mph slower (~75mph with the 14x8 down to ~65mph with the 14x6) . Would that be a problem?