Might as well report how it went to finish this up.
Got it on the RV perched on the end of the Winegard batwing mast with an adapter I built. Mast can be raised to give antenna more height same as with batwing. No need to rotate the mast from inside like with a batwing.
Issues:
1. This is indeed too flimsy to use as an RV antenna, but I will use it by mounting it only when parked and taking it down when RV moves.
2. The coax that comes with the antenna is connected inside the housing with the rotation motor etc up there, so you can't disconnect that end and use the coax in the Winegard mast down into the RV.
I don't dare cut the coax and add standard connectors so it can all be more flexible for set-ups. This coax is thinner than normal TV coax--not sure normal connectors would even fit. So I am leaving it all as is and working with it that way. Lucky for me, it works for me as is with this RV
(Gets perfect reception, so thin coax not a problem for that)
So I have the coax down from the antenna going inside the RV by a window I can close on it and it goes to the controller from there. (Not supposed to slam a door on the coax and kink it, but the window has enough rubbery sealing to allow it to close enough to keep the mosquitoes out and not kink the coax.)
3. The rotate button on the controller stays inside so you can't see the antenna rotating. The remote they give you with a rotate button on it doesn't seem to do anything, outside or inside--no idea where you aim it to get any action. It indicates power light when button pushed so batteries ok. If it only works when aimed at the controller, then might as well just use the controller since you are inside and can't see the antenna anyway. Useless remote!
4. I need a place to stash the antenna in the RV (along with its long coax attached), but that is easy in this RV. Might be a problem with anybody else's.
5. You have to be spry enough to get up that back ladder onto the roof :) (You take the coax with you up the ladder and then haul up the antenna by its coax. Reverse for getting it down.)
So really, this is not for an RV, but I like it better than the batwing or Jack, where you have to aim it by hand inside and it won't go all the way around. That was ok before with TV, but with digital you have to aim it just right. That blank arc in the Wingard mast rotation can be a problem for aiming digital.