I may be able to clear up the '12 x 6' prop issue for you Duane, all the texts, and even supplied in the kit of the Orion, mention a 12 x 6 prop for the K&B/Veco/Lee 40/45 engines of the time. Small props and high revs are a much later aberration, to extract maximum horsepower from a small engine. Even my LA.46 likes an 11 X 6 in preference to anything smaller, and Taurus flies much better with the bigger props too.
Evan. (Purchasing wood)