I had a little time and some fuel to finish using up before winter, so I ran the Sportster .20 Davis conversion again. I ran two props to see what happened. It ran well, throttled nicely (I still think I may need to modify the idle disc to allow slightly richer idle mixture) and overall did well I think.
APC 13x4W - idled at 1,800rpm and peaked at 6,600rpm
APC 10x5 - idled down to 2,200rpm and peaked at 10,800rpm. This one seems a bit small since the compression adjustment had to be within 1/2 turn of bottomed out.