If you mix a gallon of 10% nitro with a gallon of 15% you will have 12.5% nitro fuel. No BFD for sport flying the normal 2 stroker engines from .15 up to .90. If you're a choppers person, you may wish to remain closer to the same for all flying.

I have 5%, 10%, 15%, 20%, an sometimes 40% in the barn. When a few gallons used for specialties get low, there are times I mix all the low containers and sport fly the 25 --60 engines with whatever it produces. [X(]

Now I use fuel with some castor oil, except I may use an all-synthetic for some balky 4-strokes, however let me say that I don't do much 4-stroke time. I have found that 5% nitro with 16% oil, castor-synthetic 20-80 blend, does very well here in SE TX even at those near 100* days with 95% humidity, for .40-.75 engines. Those great little LA engines need a tad bit more oil so I up to the 18% oil. Below .40 more oil needed as they get smaller. I run .049 engines with grand kids CL in my back yard. 10% nitro with 23% castor oil runs just great in .049s yet so many think that 20-30% nitro is needed.

So off the tangent and back to earth, glow fuel is glow fuel and most of the major brands are very good. I have just preferred Wild Cat since its inception.