While I'm at it, I might just mention what I know about hirds, if it could be to any use.

Hirds were small bodies of men, used as personal protection to a certain person. Hirdmän/hirdmen were mostly sons of some nobleman, but who were the third or fourth son in line, preventing them from gaining any profitable heritage, or making them "unmarriable". They could of course be bastards (frillosöner) but that wasn't really a disadvantage untill the 13th or 14th century, when christianty had finally rooted properly.
Anyway, these sons or heirs tended to join a hird for some nobleman (mostly a friend or relative to their own family). There were juridical limitations of how big a hird was allowed to be, depending on the class of the person "owning" the hird. For example, the bishop of Skara was allowed to have a 12 men strong hird, but this of course varied from time to time. The biggest hirds were in the hundred or something, IIRC.