with a power commander multi function hub, you can change maps with a handlebar switch. E85 requires the use of 40 to 50 percent larger fuel injectors, to compensate for its 40-45 percent increase in fuel demand. The change in stoichiometric AFR from 14.7:1 with gasoline to 9.76:1 with E85 is 66 percent, but the resulting flow needed is only 40 percent greater, due to E85's higher density than gasoline; i would make a pure E-85 map, and a map for E85 mixed with gasoline while on reserve. mixing the two will be fine, as long as it is tuned for the mixture.