I'm all for 3 or more blades because there is more surface area to impart thrust from. Since we have a prop disc limit of 66 inches on our airframe, adding blades is the way to go to improve thrust. There is a limit to the amount of HP a given blade can absorb and transmit. I wouldnt necessarily be opposed to trying a 6 blade variant either, provided we are making full power with our engine, or later with the turbo.

David;

I'm quite certain it is not as simple as more blades equals more thrust.
More blades equals more rotational drag, and each additional blade getting a
smaller "bite".  If you are allowed the diameter needed to absorb the power,
two blades usually gives you the highest top speed.
But a 3 blade is nice for a pusher; the general opinion is it is smoother
than 2 blades because both blades are not in the wing wake at the same time.

Al