Well, I remind you again of the lawsuit over the use of glutaraldehyde which is pending in Australia. There was a lengthy thread on this subject over on Photo Net about a year ago.
In fact, X-Ray film processing was revised (IIRC) to remove the glutaraldehyde over this very suit. The fumes are not immediately annoying as are those of formalin, but they are quite bad over the long haul, from what I understand.
I don't like the odor of Glutaraldehyde or Succinaldehyde not to mention Formaldehyde. Glyoxal works for me and the odor is not objectionable when I have a whole room full of coatings hanging up to dry. And, the material is hard within 2 - 4 hours.
I have had some hardeners set the gelatin in the can before I can begin coating. Glyoxal does not do this unless the pH goes too high.
I remind you of another hardener that is not often mentioned. That is mucochloric acid. I have used that a lot, but not recently.
PE