Thanks for the note Geezer
Unfortunately, most f the time, there is no choice for non ethanol fuel. Most filling stations are carrying 10% to 15% mix. In states like Nebraska, the mix can go to 20%.
I've considered installing an AFR gauge, but that would only help rejet the Weber accordingly. Once "tuned" the gauge would be of little use.
When I return to Baton Rouge, LA., my friend has an in floor dyno which I can use to tune the truck.
Meanwhile, I am happy with 21 MPG, and it may improve with "easy" driving.