Mike,

As usual, I go contrary to conventional wisdom.  I am presently using only one OS LA46, on a Cardinal profile with 2 blade Zinger 12x5.  Take off at 7900-8000 rpm, 62 foot lines, eye-to-eye, Powermaster 10/22.  The down side of this set up is that it seems to need more fuel to fly the pattern than the high rpm type run.  Flew this at KOI a few weeks ago.

My point is that the engine will take more prop load than some applications would indicate.  One of the Master Airscrew 10x5 props might be a good place to start.

Cheers,

Jim

I have a La 46 in a cardinal with a three blade 10x7 Master air screw which is really a 10x5 and works great. A three blade 11x7 air screw, which is a 11x5 is a little to much for the 46. I picked up a three blade 10x5 Master air screw at  the local H.S. and it pitched out to a 10-3 1/2 on my gage.
Willis

Aah, a useful post. I will try the Master 10/5 3 blade shortly.

Ah, Hah!  A non-negative comment!  How about that!  Still unnecessarily sarcastic, but looking at the sig, to be expected I suppose. 

You can try a Bill Lee 3 blade prop. they have narrow blades cut a 12" down to 11.3 x4 should put you in the ball park.