I've been mixing my own of late, tried 25-25-50 (NOM) then 20-20-60 and 30-20-50, I felt that 20-20 ran better than the 25-25, and the 30-20 only produced about an extra 300-400 RPM on various size props, so I'll think I'll settle for 20-20-60 as the nitro is quite expensive and the extra RPMs are not too significant.