I saw this earlier and hoped someone who had used this lens on an 11x14 would respond to your inquiry. Since there has been no response, perhaps what I can tell you from its use on an 8x10 might be of some help.
With the camera movements centered, I tried focusing on some distant targets that were finely detailed with the lens at approximately f10, which is wide open.
At a distance of a little more than 3,000 meters, in the center of the image, the suspension lines for a cable car are sharp, but becoming fuzzy in the corners while the latticework on a construction crane 760 meters away is acceptably sharp all across the ground glass.
With the lens stopped down to f22, the cable car lines are sharp enough on the edges and there is no issue with the details of the latticework on the crane.
However, with movement, using front shift, it seems to me that there is an unacceptable softness of the image in the corners. If I shift the lens at the front and use as much rise as possible, there is a definite fall off on the edges.
From this, I would think that the lens would not be one I would want to use on a camera as large as an 11x14. Also, I remember, when I was thinking about getting the lens, I saw where someone from Rodenstock made the comment that they would not recommend the lens where the focal length was not two times the longest dimension of the film. From what I can see, on the 8x10, with the 480 being somewhat less than that, their recommendation would be a reasonable one.
I will say that, as a practical matter, the images I have gotten on film with this lens are very sharp and I have been very pleased with it. Perhaps someone else, who does have experience using the 480 Ronar on an 11x14, will weigh in and tell us about it.
One other thing, I assume your lens is in a barrel mount. If so, it would have originally been optimized for 1:1 and not for focusing at infinity. Mine has been mounted in a shutter and this may make a difference. The larger Ronars I have, that are still in their barrel mounts, seem to perform well when focused at infinity, but I have never had the opportunity to compare lenses of the same focal length against one another, so I cannot say how much difference the optimization would make.