roller ball bearings are called roller bearings too...
If you refering to cylindrical roller bearings then you are correct no on uses those. Most high performance 2 stroke or 4 stroke glow engines use a roller bearing on both ends of the crank shaft, you know the type with the rolling balls in them.
If you choose to use castor oil, hey man knock yourself for a 6. The facts are that castor is poorly suited to modern glow engines just like smoking is poorly suited to your lungs.
Use it don't use it.