As long as the engine is operating within perameters, and oil pressure is good, increased wear isnt an issue.
Anyway, Im back and found that in every gear, at speeds from 30 mph, up to 70 mph, the taller gear yields the better mpg. And example....Second gear at 30 mph was about 21 mpg. and the MAF was getting 21 to 23 gps air flow. At the same spped in 4th, mpg went to 31, and the MAF was flowing 17 gps. the biggest difference was at 43 mph, where in 5th, I was getting between 35 and 38 mpg, and in 4th it dropped to 22. At 70 mph, 5th gear was getting 22, and 4th was at 19. Not a big difference, but I was also being hit with a 30 to 35 mph headwind.