HABS/HAER/HALS has come out with new rules (May 2010) that formally allow double weight paper, so now you can use any glossy (air-dried) double weight fiber paper. The guidelines are on the NPS site, and I have them on my website as well.
The Digital print card formatting is not well explained, NPS did a better job in a (now-deleted) Request for Proposals earlier this year. I posted that with the new guidelines on my site as well, I'm sure they will codify it somewhere someday. Frankly if you have a darkroom, it is easier and faster to print them in the darkroom than scan and print them as inkjets...
Stephen Schafer | Schaf Photo
Architectural & Documentary Photography
Ventura, California 93002