Klotz is good oil. It was invented as a synthetic castor oil in 1959. It is used by at least 6 major glow fuel manufactors in the USA. Cruel Power didn't get this nickname for no reason. I would run 20% total oil of KL200 only (forget the blend) and stay with 20% nitro like YS's main recommendation...........Nitro is corrosive when burned and eats metal. You should see a long term difference in engine life. Now if 100-200 more RPM is critical to you then opt for the 25-30% nitro and buy the engine parts. I know guys will chime in and say they run 30% nitro forever and no problems. I had one guy tell me he ran 50% nitro for 30 years and never one problem. Funny he had 50 engines all the same size............