G'day John..castor is by far the best oil for our engines except it tends to carbon up a bit after quite some time. We're lucky here in Oz because we can get Castrol M, not that it's all that cheap, I think my last 5 litre can was about $80. But methanol is cheap and most Shell, BP or Ampol fuel depots have it in bulk or 20 litre drums. Shell has 3% acetone already added which can help with the idle if you don't use any nitro. The only fuel I use is straight 80/20 all castor and never had any kind of problem.