So while digging around the Link software and available configurations I can use, I've found the following for setting up the Link G4 RX ECU for Flex Fuel. There could be more options available, but if there is I haven't been able to find them yet.

First method is by using the 4D/5D overlays to adjust the Fuel delivery, timing, and boost (If using the Link as your boost controller) based on ethanol percentage:



This method will get the car to run on either. However it will be more optimized for the base fuel that it was initially tuned with and leave alot of available definition / optimization on the table.

The second method is to use the 4D/5D/Dual Fuel tables as stand alone tables and use the Virtual Aux to switch between the different maps based on Ethanol percentage:





This route adds a lot more definition / optimization for the different ethanol levels, but would still have some in-between areas of optimization as the ECU has four available tables for both fuel and timing (Main, 4D, 5D, and Dual) and three Virtual Aux's to make switches between the Maps.

The final method is to use a combination of an overlay, multiple tables, and virtual Aux switching. As an example setup the Main Fuel / Ignition tables as the 93 tune, Dual Fuel / Ignition tables as the Tune for E85, 4D Fuel / Ignition tables for a 50/50 mix, and then use the 5D as an overlay that spans all 3 tables to compensate for the in between areas.

As stated this is what I have found so far. Currently there is no available option to make adjustments to the timing split so your timing split is static and will not change based on ethanol percentage.