FLG had a customer who insisted on having one of these rigs put on a real antique Ethan Allen Single Shot to brighten it up as a wall hanger. It was a chore even though not required to aim the gun to shoot.
On the other hand I once saw a brass Tasco or Hakko in shop made mounts of the Cataract type, similar to the Chinese Hi Lux I linked. That would have worked.
One tester reported that the Hi Lux was ok to set and forget but was not precise enough for range to range comeups target shooting.
DZ and MVA make quality outside adjustment mounts, but much more expensive than Hi Lux.