Wish that was true but it isnt always. There is one blender station here that still shows about 75% ethanol. You can buy a tester from quick fuel that is easy to use to test before you buy. There is 3 or 4 different blends that they sell under name of e-85. Depending on what time of year you try to buy it. Locally they sell e-74,e79,and e-85. Bad thing is they don't drain tanks when it warms up so depending on how busy station is depends on when you will finally see e-85. Usually I will buy a drum of e-98 when it starts getting cold or I notice the percent change at pumps and mix my own.
Rob carbs are awesome. I am running one of ther 950 hp on my car. Had to only make a couple jet changes and it was good to go. As far as hard to tune not sure. My car changes roughly 4mph from 70* weather to 108* weather which isn't bad. I normally run with in a tenth on et unless temp changes more then 10 or 15 * during night.
I am running between 12:1 to 12.5:1 cr with no worries on e-85 with braided steel lines and a A-1000 fuel pump. You will use between 33 and 40% more e-85 then gas but it also help run a little cooler also. Mileage now that is also roughly 33to 40% worse. But compare e-85 to a race gas with 104 octane and probably worth it