Some folks have had varying amounts of success using a V-box to move standard actuators. The V-box converts diseqc commands into actuator movements. I think problems arise if you get too big of a dish though. According to a Superjack tech. support guy the current the V-box outputs is just barely adequate.
I would think so. There are more factors involved than just the length of the arm, but I can go as far west as w7 and can go at least as far as Intelsat 805 to the east. I'm using a 24" arm, controlled by a 4dtv 922.