Pe suggested I try 20 on mine and move up in small increments until I found the right amount. I started there and worked my way up to 32 where the idle was pretty rough. The top rpm's didn't gain any more after 28 so I moved it back there. The idle is OK there as well so I locked it down and flew it for the first time this weekend. It runs much better than I expected. Since I am stuck running 16:1 gas to oil your timing might be a little different with less oil. I am thinking the oil might slow the flame down initially which is why I might be needing the 28 degs. I have to say though that is where my Zenoah G26 runs it's best too. I just would have thought the smaller cyl. and combustion chamber wouldn't need as much timing lead. Mine runs 30 mins in the air on just about 5 oz. of fuel. Good luck and let us know how it runs.