Boy! You Aussie's run alot of castor! I was running these engines on K & B 100 for over thirty years. K & B 100 was around 8% nitro and about 22% Castor Maybe. Never knew exactly how much castor was in that stuff, just know it sure was a slimer when it got done. Now I use red max 15% & 10% Nitro 20% Caster and they still run just fine.
With 42+ Years running all my U/C engines, I still run them breaking to two stroke on elevation and they still all run just peachy!

Fox 36X and Combat Specials as well as Enya and ST's all ran on K & B 1000 now they also run on Red Max 15%.

O & R an McCoy's as well McCoy/Tester's are all running on 10%Nitro 20% Caster.

Anyhow glad to hear the Aussie's are still flying U/C take care guys.