I have a 2005 Suzuki C50 with Memphis Shade 21 inch windshield. I am getting 50mpg if I hold a steady throttle at 70 mph on the highway. The C50 has a 4.1 gallon tank. I am going to ride from Alabama to Arizona this summer.I am thinking of buying a C90T which only has a 3.7 gallon tank. What kind of fuel economy can I expect from a C90T?