Just mix your 15/17 omega with methanol as you propose 100 units of glow fuel and 70 units methanol and mix this fuel with gasoline at 2 parts gasoline 1 part your mix this should give you a 2.9% nitro and 3.3 % oil mixture which is close to the 3.3%nitro and 3.3% oil obtained with the 10/10 fuel and forget adding the 20/10 car fuel.
This should work great with the conversions because we dont need alot on nitro in them because of detonation.