Hi Rod,
I know where you live...
The website lists everything from 87 octane to 94 in your state. Your local marina sells 90 octane, you can get 89 octane at a marathon station without trekking to the marina... You can buy 100LL Av Gas from your local airport. I would mix 1 gallon of 100LL in with the 90 octane or the 89 octane clear gas and you will end up with a "very happy mix". The lead in the 100LL will bump the octane in the unleaded portion...
Back in the mid to late 70s - regular switched over to unleaded and premium was still leaded. We could mix the two together and end up with a higher octane than either of them alone - for example mix 87 and 94 octane in a 50/50 mix and end up with 96... the lead in the premium bumped the octane of the unleaded portion of the fuel mix. Later on they cut the lead content in the premium and this didn't work as well...
My ideal mix is 1 gallon of 100LL av gas added to 4 gallons of 94 octane clear gas... happy, happy, happy... But 94 clear gas works well by itself too. If I can't find clear gas - I will mix 100LL with e10 pump gas - 1/4 to 1/3 100LL to cut down percentage of ethanol in the mix.
jeff