I happen to know "useful" pool players that use differnt tip (harness levels) depending on the game being played. So, in straight 8-ball he might use a medium-hard, and for an 8-ball derivative like 1-15 (where delicasy is paramount) he will use a medium (a triffling softer).
If you do not like manicuring your tip (reshaping, de-mushrooming,...), stick to the medium-hard to hard end of the durrometer. These tips take a more deliberate stroke than the softer tips.