don't know he has in his gas but.
all stations in Fl have a notice of ( up to 10% ethanol) some stations also have pumps that say NO ethanol.
the no ethanol price is about 50% more than the regular, but the octane is up,, Oh! E85 (85% ethanol) is 108 octane.
3 gal of e85 +7 gal 93 =97.5 octane or maybe 98.1,,,,counting the 10%
3 gal of e85 + 7 gal of 91 = 96.1,,, or maybe 96.5 counting the 10%
3gal of e85 + 7 gal 89 =94.7 or maybe 95 counting the 10%
maybe you can do your own math and put in the octane you want.

PS found out they reduce the octane in all gas and then add the 10% ethanol to bring it back up