I tried lacquer on a few models today. They are still drying (and I'm waiting for my head to clear--That stuff STINKS!)
So here's what I've learned:
Safety first: Use a well-ventilated room! My wife actually banished me to the back porch, which is a bit chilly this time of year (it's 30 degrees or so right now, so at least it's above freezing).
With that in mind, I didn't just want to attack my siege tank with the lacquer. I've put too much time, tears, and profanity into that thing to screw it up now. I made a test box, and covered it with different types of paper, odd bits of cardboard, and even made sure to use the three different types of glue I use (White school glue--really runny, Elmer's craft glue--tacky, and superglue--when I want to become one with my model

) In case anyone's wondering, I used a cheapo disposable sponge brush. I'll save my good brushes for actual paint.
After that, I started painting. I was surprised at how fast a light coat dried. It only took about a minute. I noticed a few things. First is that the lacquer won't really soak in where there is glue, and second, it tends to darken the areas where it does soak in. You can see here where I've painted a few sides and left one unpainted for contrast.
It also soaks through plain white paper more than cardstock of any type.
Since it seemed to work well, I went ahead and painted the
Jotun I'm working on. It was a happy accident, but the magnets I put in the joints came in handy.
Once it's dry, the laquer leaves the painted surface harder. It almost feels like plastic. I've used it on wood before, but never on paper. I'd recommend laminating or reinforcing whatever it is you are painting beforehand, just to help prevent warping.
Hope that helps y'all!