Ed,
BVM has the best instruction manuals and insrtruction sheets in the business.

On the UAT instruction sheet, side 2, there is a paragraph entitled: Defueling-

Quote: "If it your normal practice to defuel the model at the end of the day, leave the fuel in the UAT for easiest next sttart-up procedure. Of course, if the model is to be air transported drain all of the fuel system completely."

Also, the instructions show mounting position information, fueling procedures, first engine start, posat flight checks and additional operating tips.