HB FP with Xtreme or GWS DD Tail

Anybody uses Xtreme DD Tail on their HB FP? How do you like it?
I don't like too much, it reduces my flying time. Usually I can hover +/- 10 mins, but with Xtreme, only around 5 - 7 mins. After 5 min, the nose will go left, because there is not enough power on the battery going to the tail motor.
I want to try the GWS motor, but none sell the motor around my area. I think the GWS motor is not as big as the Xtreme motor and hoping do not draw much power as Xtreme motor.