i dont know if it helps with these motors (that are on the ragged edge of compression) but in my jetskis i am pushing some high compression with no problems running 110 gas and heat coated pistons, which i was told i should be using 112-114...
sure for my 2 cycle not a big deal, i forgot off hand how much coating is, but add that expense up for 8 cycls, it could get costly, and as mentioned here there are many variables that play into preventing the pinging and damage
i don't know if coating pistons would allow you to say run .25 more in compression or not
but on the skis it allows us to run tighter ring gaps too
fuel quality also depends where you are as well
i'd love to run 87 octane that makes some nice power and has a killer idle as well
as i say...
live by compression.... die by compression...