knarf, here is an alternative to your question about the .46 sized conversions, an OS LA .46 with a Davis Conversion Head. I'll copy and paste what I had to say about it when I first got it.


I converted the LA .46 with a Davis Diesel head today and the results are great,
Davis, Oily Mix/ Plane fuel
MasterAirscrew 12x6 three blade 8,800 rock steady, does not wander, still working on the idle 2,500 so far. I'm flying it tomorrow. Throttle up is clean and crisp. I could squeeze about 9,000 rpm out of it but it wanted to hunt between about 8,900 and about 9,050, I reduced the compression slightly and it settled into 8,800 as mentioned above. This was on Davis Oily mix or Plane fuel as he calls it.