I ozonate oils commercially for sale so I have a bit of experience.
In answer to your question, the greater the concentration, flow rate and dispersion of ozone into the oil, the less time it takes for fully ozonated oils. I use an ozonator which produces 8 grams of ozone per hour and run it at 3 lpm. Three gallons of ozonated olive oil is produced in about ten days. Don't bother with Chinese ozonators for this purpose. You'll burn them out in about a week.