[-=[XTC]=-Body Bagger]

I have a good sytem, but also have the same trouble moving large prefabs.
What i do is, make a base for the building on the map where its final position is going to be. Then save that as a prefab. Load it back into radiant build the house, re save it as a prefabs then load the finished prefab back in to my map and voila.... its in the right position , no moving required
Craig