yeah... I've read that paper before; but doesn't say much about effects on image deterioration. I've read somewhere else (perhaps some Mike Ware article) that albumen in a long time can do harm to the print for example. Of course we're into the area "it's not my business anymore"
The varnish I have here is designed for "oil paints, acrylics, pencil, pastels". The label says: "16% chetonic (?) resin, 49% distilled petrol compounds, 35% GPL propeller (it's an aerosol), UV filter" - "Highly flammable, irritant".
It's a rough translation from Italian.