Hi Veggie,
1. I used a CA110 propane carburetor.
2. Still use the decompressor for starting since we're using a relatively wimpy Gast 4am w/rubber roller starter.
3. Yes, the compression was lowered repeatedly to where we had no knocking at full load. A total of 0.6 inches of aluminum spacer and gaskets. I believe we could have a bit less since changing to the Garret KN type regulator. That regulator also make the carb rich/lean adjustment work properly. To accomodate the 0.6 inches of head raising, I added to the length of the shorter pushrod, and moved the longer pushrod to the shorter position.
Yes, all this is covered in the prior pages.
The engine has logged around 700 hrs so far, and has been problem free. The oil stays in pristine condition, looks like it just came out of the can. Mostly it's running the air compressor for construction projects, plus generator (ST-3) for well pumping while running the washing machine. Someday I'll get my air skill saw back.
I'm happy with the result. My health and enthusiasm for non-essential projects is waning or I'd do mine. My neighbor is happy to not be hauling and handling diesel fuel. It's pumped into his main propane tank which serves 15psi gas to the pex-like plastic distribution lines, down regulated at the engine room, shop and house to 10 inches of WP.