when leaded gas was outlawed for the street, there was something I read about the diminishing return of octane boost with lead, if you doubled the lead, the octane only came up a fraction, and the same was true with lead free boost agents, but the article stated that if lead booster or leaded premium was added to lead free premium, there was a larger octane boost than by adding the same amount of lead free booster, so mixing a little 100ll with your 92 may get you to 95 without changing the volatility much.
Whatever happened to 100/130?