Well, that's a fairly wide range of bikes you've mentioned. What model of Harley do you have; sportster, softail, dresser? What kind of riding are you looking at doing on the Duc; around town/commuting, sport/light touring, track days or spirited street/canyon riding?
We need some more info to give you a more accurate opinion.
Oh, and BTW.....you're going to get the "don't buy a 848/1098, you'll kill yourself" crowd jumping all over you since you mentioned that you don't have any sport bike seat time.