I'm preparing to do a service that requires a 16 - 17' mast(The property slopes away from the street and the POCO's lines are on the opposite side. The meter pan's location will be on the back side of the garage peak, so I'll need to project far enough above that so I'll be able to have a 18" drip loop.). I have a 7' piece of 2 1/2" gal and need to get that threaded to be used as the bottom piece. I spoke to a master plumber and he said that most plumbers only go as far as 2" pipe. The orange box store said the same. Any suggestions? pete