Is it sound to use acrylic medium instead of the regular gilding paste to attach imitation goldleaf to a rigid, gessoed support? Is it fine to put acrylic on top of said gilding? Would there be any archival problems with such a solution?
Some acrylic mediums can induce tarnishing with imitation leaf, resulting in a blue-green patina. The tarnish is not altogether unappealing, but may not be the desired effect.
Acrylic dispersion mediums are fine mordants/adhesives for metal leaf. I have much more concern about the imitation gold leaf. These readily oxidize even under solvent bourn varnishes. They are really not stable in terms of color and they easily tarnish. If you really need to use these copper containing metal leaves, I suggest covering them with a MSA varnish rather than acrylic dispersion mediums alone. Dispersions generally create a film that is less continuous than solvent bourn acrylics and are less able to postpone tarnishing. Also, as Matthew mentions, the aqueous system and resultant pH of dispersions can patinate rather quickly.
