Hi Hewy, I you're only interest in hitting steel plate or other big targets, you don't need to do anything with your Uberti arbors. If you intend on target shooting, hitting where you aim, you need to fix the short arbor. or use a workaround.
I have experienced that when the wedge of a short arbor Uberti is hammered in with the barrel/cylinder gap ideal, the restoring force of the barrel wanting to spring back keeps the gap the same until the wedge is moved. That suggests a workaround for the short arbor by using a leaf gauge to set the gap. As long as you don't move the wedge during a shooting session, that workaround is effective. However, if you use conversion cylinders, like me, changing cylinders after a cylinder is shot is a pita for resetting the gap.
When you change the barrel/cylinder gap you change the poi.