I've used Stihl, Husky and No Smoke two cycle oils and
haven't had trouble with any of them. I can say that the No
Smoke doesn't burn my eyes as bad when in confined areas. My
local saw shop owner claims that Stihl oil is designed specially
for Stihl saws but like I said I haven't had any trouble with
any of them. As far as the octane, I run the cheapest and haven't
had any trouble. Hope this helps. Mike