A painter's two cents:
Glazing is an old and honored oil painting technique. Applied evenly and thinly, a glaze can alter the perception of a color or surface without being intrusive. Traditional glazing mediums are made with thickened linseed oil, damar varnish and turpentine, with a few drops per pint of copal drier. (Mineral spirits will not dissolve damar and cannot be used) There are lots of recipes and and people who swear at or by each one. There are also many commercially prepared glazing mediums, the most widely known and used of which might be Liquin, by Winsor Newton. This is a bit gelatineous, but very easy to use and, IMHO, the best product out there for most oil painting needs.
Now the problems. Glazing may impart a gloss on the surface that is quite different from the paper surface, depending on the amount of glaze and the receptivity of the paper. You may also end up leaving brush strokes that will catch light if you are not careful. The traditional way to add thin glazes is to stipple the glaze on with a very soft brush. The key word is "thin." Test, test, test!
I've used Liquin on fiber paper and on RC. It works well in coloring a B&W print and allowed me to get an effect similar to illustrations made in the 30's.
Archival in themselves, glazes have been used since the Renaissance and have proved themselves quite stable. The very act of putting linseed oil in contact with paper is suspect. The chemistry of how the emulsion will react long term is beyond my humble understanding. An isolating layer of some varnish designed for photography might be helpful, though I know very few people would go through this additional step.
There! free advice and worth every cent.