The way I've been doing it works just fine and I don't go as high on the Nitro as we (a few drag racers here) use to in the mid 80s. Back then we would go as high as 70%!!! Hell we were destroying engines every week because we were mixing high nitro fuel, cutting the crank and exhaust port timing and grinding away on those little engines. Of course we didn't know exactly what we were doing but, much has changed since then and my engines doesn't come apart now days. They are screamers too!