Dewey, I would suggest going to a fitting center and hitting the balls to specific distances you need to avoid gaps.  You will quickly discover what lofts you need vs. guessing...if you are unable to do this then I would recommned you examine what wedges you need.  For instance, some guys like a PW, GW, SW, and LW, others prefer just PW, GW/SW and LW.  I prefer the first set up so I would think you would need at least one wedge with some loft/bounce for sand shots etc... thus the 58 makes sense while the 52 can be played with various distances.  Unfortunately, it is all subjective. 

Good Luck!