CAP 232 40 engine?
I have no personal experience with the .63 yet, but the APC 13x6 seems to be the popular prop.
I am thinking of also trying the bolly Clubman 13.5x6
From what I read, the engine likes the 10,000 -11,000 rpm range.
So prop it with what ever suits your flying style and keeps the rpm in that range.