I scratch built some similar 1/2" arrows, and fletched them with cut Tru-Flight long feathers, at 6" or 7". The first feather was aligned with the nock insert. The second was just short of the insert on the opposite side. The third was positioned by eye mid-way between the other two. Not perfect, but close, and the real ones probably weren't any more accurate. I used Bohning fletching tape and applied the feathers by hand using a clamp without its jig. They were whipped with jeans-weight sewing thread, sealed with Satin Minwax Polycrylic.
Answered on 12/4/2012 by Mungo Napier, Archer of Mallard Lodge from Atlantia, SCA