HI
DO YOU WANT your plane to be clean OR do you want your engine to run real good and last a long time -,the choice is yours -,you must use some castor oil in a two stroke glo engine if you are looking for long term performance and longevity-,-clean the plane and get over it ! -full syn fuel does not give the metal protection that castor does when engine temp rise and MAY cause serious damage
i run 15 % MORGAN OMEGA in all my glo engines,per CLARENCE LEE not a good idea to reduce the nitro % as the piston and linner will not produce the same head temps,so the parts will not expand and seat to each other as they were doing before
i find it best for engine life -,to run a given engine on the same % and brand of fueland use one size prop ( once you properly prop your airframe )
building ,flying and running two cycle glo engines for 26 years-,MORE THAN MOST-,less than a few
ENJOY BEST RGARDS TONY