I had the same questions (plus some others) after trying to encode a
sample finding aid.
1. With regard to the "level" attribute for <c>, I only set the attribute
at the series and sub-series level. Below that, our entries can be any of
a number of levels, depending on how much we used a hierarchical
formatting to generalize over a range of folders and to eliminate
We would do:
Meetings: Washington, D.C.
Meetings: San Diego
When this starts going down a few more levels, these general headings (not
really sub-series and not really files) can be impossible to tag
consistently and without using multiple levels of subs
I opted to 1) use the numbered components <c01>, <c02>, etc., and 2) did
not set the attribute beyond a "real" sub-series.
2. I had the same question about whether the <unitdate> is part of or
separate from the <unittitle> and opted for the former, based in part on
the fact that the dates are considered part of the title field 245 in the
MARC-AMC format. My reading is the same as Alvin's - either is legal as
the DTD is written, so it's a matter of convention.