Mid summer isnt a problem... but I check the drop sheets at the station to see what the percentage of alky it is.... they drop X gals of alky and X gals of regular into the same tank OR you can get a tester from Quick Fuels
I tried this, went to 4 different places , asked the attendants, you would have thought I asked them to explain Nuclear fusion. In fact on the pump it states to ask the attendant which blend is currently being sold, They didn't know anything about it.