Find out the holding capacity and index it for the efficiency rating. There's no formula "rule" but if (for example) you know that they both have the same holding capacity, the one with lower efficiency will last longer in service without becoming saturated. There can be exceptions, but generally speaking that would be how I would determine it.
Keep in mind that most of the stuff filtered is produced during the start up/warm up cycle. You pluck some stuff out of the oil as it fatigues, but the majority is produced during the fuel enrichment part of the driving cycle. So there is no "mile" rating on a filter. That is, a 15k filter isn't necessarily a 15k filter under all circumstances. It's a 15k filter when 15k is accumulated over (something like) 1 year of service.