to add- we have gone to "very high " oil concentrations -32-1 with as good or improved performance in all cases on pure synthetic..
No oily residue on bottom of model.
these are all synthetic oils - Klotz Model lube/ Redline Racing two stroke -etc..
Even using the plain ol Pennsoil two stroke air cooled - we get nice clean engines -BUT if you set the needles incorrectly - this will carbon badly .
It ain't whatcha got -it's the way that you use it --(old song)