Hmmm. Tough one. Try indexing the wheel spokes with a marker to the exact point the ring should be in to center it. Now find a way to prevent the ring from going past that point, wire tightly wrapped around the spokes, duct tape/painter's tape, etc wrapped around the spokes, popsicle stickes cut to length and taped to the spokes from the rim in, anyway to stop the ring in the proper position. Then gently tap the ring into position and superglue the ring to the spokes. I agree, the tensioner shouldn't move but a smidge. Don't get frustrated and give up. You will find a way.