I have a 60-inch and 62-inch recurve from the same bowyer, and at my 29-inch draw, the 62-inch bow is noticeably smoother to draw, despite being 3 lbs heavier in draw weight.
You mention you already have a 58-inch and a 62-inch from the same bowyer; I would think you should be noticing a difference in comfort, smoothness, etc, between those two which should point to the 60-inch being 'somewhere in between'. If not, then it is simply a matter of personal preference in length (shooting from blind/tree stand, etc).