It finished at 3.6 PH, which was perfect for me. I do believe the more sugar the yeast has to eat, the more souring potential it has. Also I think the temperature plays a part in the souring potential, the higher you go the more sour it can get. I think a 4.5-5% beer gives the right level of sourness.
It was a little on the slow side to ferment, as that yeast makes lactic acid first and then the alcohol.