XE285HL in 360

If you are going to run our 98 octane & 10.8:1 static CR, there is a good chance you will get detonation with alum heads & almost guaranteed with iron heads.
What are the 3 basic numeral grades available to you In Australia?
In the U.S., it 87-89-93. Where does your 98 fit in. Normally it’s the top grade available correct?