8R19.5 tires are tall (31-33") and skinny, and should get reasonable mileage in comparison to the other sizes you're considering.
They look good on a 1 ton truck too in my opinion.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-