Janice, why do you want two fuel guages? If you leave the crossover line open the two tanks will equalize and you can put one sender in the rear tank, which is the lower of the two tanks. The best location and way to install a sender is to use the tube type and cut a 2" hole in the top of the rear tank with a hole saw. Grease it up good so the shavings don't drop into the tank. You can access the location (hopefully) under and just forward of where the rear cross seat was. After you get the hole cut, take a tape and measure the depth of the tank, you will need that for ordering the right sender. A good place to get the sender and guage is ISS in Portland. You would have to run the wire forward under the belly of the bus. A better way is to mount the guage in the rear cabin of the bus, then it's a short wire run. JMW