max-prop diameter

I hope this is not a rehash as the board has seemed to refuse my
posts this evening.
I have the same engine/gear as you and had a 16x11 3 blade fixed
prop. PYI told me to go with a 16" dia 3 blade Max. I did not
inquire about a 2 blade. The 9" pitch is actually a 9.8" as it is
adjusted in 1.2" increments. I have thought of trying the 9.8, but
have not yet.
My understanding is that a larger diameter will give lower loading
per area on the blades, resulting in less cavitation and better
efficiency. I think the usual recommendation is to go with as large a
prop as will fit and still allow 15% (not the 10% i quoted earlier)
tip clearance. PYI may modify this recommendation due to the finite
pitch adjustments. Most everything I know (it’s not much) about props
comes from Dave Gerr’s excellent “Propeller Handbook”, usually found
at Barnes and Noble.
John Churchill