Octane booster = snake
oil. When they say it raises octane a full point, they really mean 1 point = .1. So... if your octane booster says it raises octane 3 points and you started with 91 octane you now have 91.3 octane.
As Bernica said, mix some 100/104/110 race fuel in. You'll more than likely only need 2 or 3 gallons per tankful.