Octane (Ug, again !)

[dferlauto]

Since octane ratings have a direct correlation with pre-ignition, does it then follow that higher octane would give you added protection against toasting valves when you're roaring down the 101 for 5 hours solid at 4000 RPMs ?
I am experimenting & find that I can lower octane without much consequence, but somehow get the guilts... kinda like serving Thunderbird wine at a wedding ...
From what I've read, I'd probably do better to use lower rated gas & go for a better brand of gas... I understand that there is a considerable difference in carbon build up, which, I suppose is the precursor to toasted internal components. I often buy off brands as gas is expensive here in silicone valley.