its 22 freakin minutes!
do some research into the meaning of octane, what it does exactly, do some hard thinking, and then make the decision.
all my experience (and the information available) has shown that the lower the octane, the more power you produce.
at the same time, if you run super high compression ratios, or really load an engine down without letting it rev... use high octane.
personally, i find it easier to let an engine rev at a decently fast speed and stick with el-cheapo low octane stuff. no detonation issues.
said it before elsewhere, i think i even had a link to it somewhere... honda found they could use 70 octane fuel in a racing engine simply by letting it spin at 16,000+ rpm!
"the faster an engine runs, the lower the octane required."
thats it in a nutshell.