Just to simplify matters, several tables are needed to be populated and dialed in correctly, and two DTCs enabled.
Here's a snapshot of the important tables, the first being a stock LS3 and the second with the FF sensor installed. JUST FOR REFERENCE.
The Flex Fuel Spark table multiplied by the PE/COT Spark Advance Correction Multi vs. Fuel Composition is what gets added/subtracted to the main spark table. Creates magic.
Of course, each tuner will have their own approach because we know whatever tuner you are working with is "more better" than "the other" tuner.
Just posting this to show it's not a overly complex process, but the numbers in the FF spark adder table are important to obtain the optimal add-spark power to take advantage of E85, but still be safe. A good dyno tune will show what's best.