Well, I couldn't wait until the week-end. I made my first attempt last night.
It worked very well with the brush. I prefer this method not only because it's fast and easy, but mostly because I like the brush strokes to show at the edges of the image. I brushed the salt solution, waited for it to dry, then brushed the silver nitrate as fast as I could. It worked perfectly, and I can see no traces of uneven coating. The only difficulty is that both solutions are completely clear, and I find it hard to assess how well they've been spread on the paper. It's easy to miss a spot. The yellow vandyke sensitizer is easier in this respect.
Unfortunately I have no suitable negatives. Even those which are contrasty enough for vandyke aren't contrasty enough for salt. You can see in the attached pictures how the same negative looks on salted paper (left) versus vandyke (right). Both prints were toned in selenium.
Anyway, I think it's OK as a first attempt. I've got even coating, acceptable d-max (not as good as double-coated vandyke, of course, but good enough nevertheless), and good sharpness. All I need now are some over-contrasty negatives.
Is it worth trying to increase contrast by adding a little potassium dichromate? I know it doesn't work with vandykes. Does it work with salt prints? I mean, does it really increase the contrast? Or does it merely clear the highlights, while leaving the rest of the curve unchanged, like it does with vandykes?
Dichromate operates as a highlight restrainer. It does change the curve as it changes the curve with the Vandykes.
The best way to see the difference, as well as measure it, is to do a print test using a step wedge.
If you want to change the contrast of the salt print, a good method is to gold tone. A little goes a very long way, meaning I can tone 10 prints in a .1% gold solution with lots to spare.
Toning before the fix bath has a different outcome than toning after the fix bath. If you can give it a try, you might like the outcome.
One may also change the contrast of the salt print by manipulating the other salts in the formula.