I've been experimenting a bit with archival wheat starch paste from Lineco for albumen prints, which are on very thin paper and curl more than gelatin prints. Haven't quite gotten it down to a science yet.

If you look at Reilly's albumen book at albumen.stanford.edu, there's a method described for archival starch mounting, which involves gluing the print to a thin substrate, like an uncoated sheet of the same paper as the paper the print is printed on, then using corner or hinge mounting to attach the print to the backing board, as is the norm in conservation circles these days.