Just got home.
Heavy rain from Wichita to Ardmore...indicated 24.5mpg. Stop and refuel.
Light rain from Ardmore to Gainsville...indicated 27.2mpg. Stop and rest.
Gainsville to Hillsboro...indicated 28.4mpg. Stop and rest.
Hillsboro to Waco...indicated 29.2mpg. Observation.
Waco to Calvert...indicated 29.5mpg. Bathroom stop.
Calvert to College Station...indicated 29.0mpg. Home.
Previous run from Wichita with the fiberglass tub averaged about 25mpg.