Myself, I'd fly it with what I was planning on running it with. A lot of times you can get pretty close with that first prop, but you don't know for sure until it's running and in the air....
I am not endorsing asking the engine to make big power for the entire duration of the first few flights! Lot's of info on engine break in around. IMHO, there's nothing special regarding break in with this one.
Last thought, Corsair might look pretty good with a 3 blade prop, and get you some prop clearance at the same time?