2 stroke oil doesn't really burn during the combustion stroke like fuel does, so it displaces the fuel causing the mixture to effectively a little run leaner.
That's why the old myth about running more oil (like 20 to 1) to break in a new top end actually did more harm than good in many cases.
Iffn you wanted to break it in softly, just richen up the needle for a while. Or build it right so it doesn't need break in, either way
At 50 to 1 or less it doesn't really make much difference as far as rich/vs lean.
If you have 50 to 1 and you mix it with regular gas the ratio gets thinned even more, so it won't hurt anything except maybe a catalytic convertor or an O2 sensor. Prolly not a good idea to run two stroke oil past a wide band O2 sensor. The metal additives in the oil would prolly plate the sensor and shorten it's life. That's just a hunch, no real knowledge on that subject.
I know they really hate silicone..............
I don't even know if they make castor based oil anymore. the new synthetics are soooo much better.
We used to run the castor oil at about 30 to one to keep the top end from hot-seizing and the stuff gummed up the rings so bad we had to go through the top end pretty often.
With the new synthetics 50 to 1 is common and they never gum up and last a long time. They barely even smoke anymore.
If they could only figure a way to make the synthetic oil smell better...........................