I don't know why any archer would pick 1h over using a 1-slot 2h (Mace, fighting axe, sickle, langes). 2h animations/reach are just so superior to 1h. Look at a Langes Messer in 2h mode:
weight: 1.8
difficulty: 12
speed rating: 100
weapon length: 92 (actual reach on side swings/overheads is about 110 thanks to 2h animations)
thrust damage: 25 pierce
swing damage: 35 cut
slots: 1
Compare that to an Italian Sword, which is slower, shorter on left swing and overhead, and does 5 less cut damage. OK, 1h thrust is a bit better than the polearm thrust animation that the Langes in 2h uses, but the other 3 attack directions are far superior with 2h (1h right swing has similar reach to 2h, but it's slow and just glances nonstop). The Fighting Axe and Mace are equally awesome compared to any 1h counterpart. Plus the 1-1.2 weight 1-handers will just be weapon stunned all the time.
Unless it's just for style, I don't see the appeal of 1h as a sidearm for archers (unless you are taking a 0-slot weapon, obviously).