Got a tester and I always test at the pump before I fill my jugs. So far the fuel has tested 83-85% every time. In Washington State, it is a state law that the fuel is a certain percentage of the rating which really helps ensure we are getting good fuel. Problem is, that drives the price up to about what Premium (92 octane) sells for.
As for carb, I haven't decided yet but the 2 I got quotes on are from Thumper and Pro System