jayseas,

Unless you have old worn-out engines, there is not a problem with the castor varnish. Synthetics or part synthetics keep the engine cleaner running. If you have problems with the varnish seal, switching to all-castor lube will get all or most of it back.

As far as the percentage of lube, many of us ruined engines back in the fifties and sixties by using popular fuels that had insufficient lube...they are no longer around.

One of the reasons we need to keep an eye on lube is that most "RC" fuels are blended for large BB engines, which require less lube. You can use the RC fuels...many do. By looking the contents up on the internet sites, you can figure what, if anything, you need to add. Castor can usually be purchased from hobby shops, or online from SIG. I'm sure there are other sourses, but I have used these.

BTW, methanol in the fuel is what keeps the glow plug working. It is a catalytic reaction between the methanol and the platinum in the glow element. Nitro makes it burn better.

George