AS far as my four engines all of the instructions say use 5%-10% nitro with at least 18% castor. What you explained sounds true but of course me being a myth buster , on my OS .46 fx I used 15% to break it in and I am not sure what the other percentages where but it was an OMEGA synthetic blend. This weekend I used 5% in the OS .46 and it ran like crap. Guess I have to start carrying to jugs of fuel.