The Schnabel Gun was the first production kit from the talented Kallamity ( Luca Z). As a tribute to Luca's own first build of the kit, I went with an orange paint scheme. I have made some additions to the kit ....I have real trouble not doing that lol.
I agree that for static display pieces like this a top layer of varnish is unnecessary. I don't bother on my display models (however like Dave, I do have intermediate varnish coats pre and post decals/oils).
Its all about finding the right hairspray, a lot of people have that problem. I use a pump spray Fructis Bamboo strength 4. Its got enough strength to hold the rock salt in place without dissolving it.