I've bought a few items from oracle for the wifes Jeep. They also make stuff for the mustang and wouldn't hesitate to buy from them.
https://www.oraclelights.com/products/oracle-universal-colorshift-led-underbody-kit-dynamic-colorshift?rq=mk_ford~md_mustang~yr_2020
I would fill up on the e85 there and datalog it. Send it back over to lund to make sure everything looks good. Unfortunately I don't think there are any station near us that have a true 85%.
I use the gas buddy app on my phone. You can search stations strictly by E85. My last tune I was lucky to get 100-150 miles in before I had to fill up again on E85.
I've heard bad thing about the speedway in South Lebanon. I've been meaning to go up there with my test kit and check the E85. I usually fill up at the speedway up on Kings Mill for E85. Didn't know Meijer had E85 available. Is it the one near Fields Ertle ?