Fermentation time

As a serious home baker, I'm learning without a net.  I have no bakery experience or the patient ear of a mentor so it's a long learning curve.   Here are a few questions to anyone who has been down this road.  I'm fermenting my stiff levain for 48 hours at 46 degrees before mixing.  I'm shooting for a more pronounced sour flavor.  Does this amount of stiff levain fermentation cause any problems I should be aware of?  Also, I'm bulk fermenting for 6 hours at about 74 degrees.  Same question, am I creating any issues with the quality of the final product?