basically, as your getting goes up dramatically, the amount oil needed to mix goes down.for example, if you are running stock with 200 mains, and your dad is running modded with 300+ mains, you would mix 32:1, and he would mix 40:1. both engines would get the same amount of oil.
i'm not telling you to mix 32:1, just goving an example. it really depends on your environmentals, mods, etc. i actually checked the oil content in my internals before running less oil in my mix.