I would put a piece of double stick tape on each of the jaws.Then install cylinder and check the runout.The tape should squeze the same amount.I would take small or fine cuts so it wouldnt take a lot of pressure.
If ya go the muffler expander i wouldnt worry about anything because its going to grip around the whole cylinder,and again take small or fine cuts.
Your also welcome for the PM.Ya might give him a call again.That man has enough experience in engines and shop equipment is as many years as ive been born.