I don't really know if 2 blades are better then 1. I fish the central basin and went out on a charter a couple of times before going on my own. he used all 2 blade harnesses on his boat. so I figured he knew more than I did so I have always used 2 blades on the central basin. but back when I fished the western basin I ran single blade harnesses off my riggers. and we did catch fish. if I were fishing the western basin now I would start with 2 blades.

I think it is more personal preference than anything else. but I catch fish with 2 blades but we fish more for bigger fish in the central basin. if your catching fish with 2 blades you can always tie up some single blades and run them on one side of the boat and see which does the best for you.