mix'n it up
at about 10% water/alcohol as a percentage of your fuel, most oil mixed in will tend to separate back out. Mix it , use it right now........ok. In doubt, set a water glass of your premix on the shelf and keep any eye on it for a week.
done that and found the oil separating out in little gobs floating to the top and sometimes just suspended oil drops floating in the fuel mix rather than a consistent mixture.
the danger today is even high octane gas labeled alcohol free has water based ethanol or alcohol mixed it to boost octane. Only test is mix and observe.