The type of commercially available, general use, vehicle gasoline has no bearing on measured fuel dilution. Your driving habits definetely have an effect on fuel dilution results. The type of gasoline might have some influence on oxidative blowby products, but that's not truly fuel dilution, is it? What doesn't get blown out the exhaust ends up in the sump as particulate contamination held in suspension by the motor oil's detergent/dispersant chemistry or, if large enough, trapped by the oil filter.