Quite a bit in the length. As per the PDF on the Winegard site, I need 66" from the front of the base to the rear of the Sensar IV. Going straight back, I have maybe 40", to be able to cover the existing hole in the roof from the Jack, with the Winegard base (before it runs into a Max-air vent). If I want to patch the hole otherwise, I can go further towards the front of the rig.
Looks like I'm OK with the width, as the Wingman would be facing towards the curb side, with no obstructions. As long as I don't try to rotate it while it's down (is that possible?).
This is just going by the Winegard web site, haven't pulled the Sensar IV out of the box yet, or layed anything out on the roof. Will be bringing the RV home later this week, and will have a few days in the driveway to get the work done before we take off on the trip.