Running a product like Sea Foam in the gas for your power tools keeps that gunk from building up.It also helps preserve the fuel during the off season.
make sure any container for fuel is sealed as alcohol is like a sponge for drawing moisture from the air.
Dirty secret of alcohol fuel:
it takes about twice the alcohol as gasoline to make the same BTU's. Hence,lower fuel mileage when they are all screaming for increased mileage.
As for weed eaters,stihls,homelites, are both good products. i would see what most pro lawncare business use locally.