Dear Modelers: I've read some of the comments on the technique. By way of short intro, I'm Mike Chorney, co-author of the article.
First, salting works in conjunction with about any paint, either as undercoat or overcoat. Of course, with enamels, some added drying time will be necessary. Experiment.
The basecoat, showing up under the 'chipping,' is dependent upon the composition of the structure (e.g., natural metal, resistant basecoating covering steel on German armor, etc.). For aircraft (i.e., the body and fixed planar surfaces), most of the undercoating was metal......however, keep in mind that control surfaces were doped linen, and would present a different color than the metallic body. With IJAAF or IJNAF, the linen was a sort of light grey-green color, so metal may not be the best choice here as undercoating. Consider, also, that the fabric would probably not succumb to the level of weathering and chipping comparable to bare metal oversprayed directly with paint. The linen would be absorbtive and aid in bonding the paint to the surface; at least, this is what pictures seem to convey.
The salt wipes off easily, and you can apply water to aid in cutting back on abrasion, if that is a worry. Other salts can also be used; for instance, popcorn salt, which is fine-grained, can be successfully applied to 1/72nd scale planes and armor. Bicarbonate works as well. Again, experiment.
The technique can be tame and manipulable, in general, but I've created a few clinkers with it which are now back resting in the box; this has happened when generally trying to be too ambitious on a subject which didn't look too good with the chipping effect extended across its surface (the Tamiya Wildcat comes to mind, here). The result can be overwhelming. I would suggest working in a small area, like the wingroot, which is masked off from the remainder of the subject after laying down the basecoat.
Practice the salt application: pouring versus more controlled manipulation with a brush. Also, watch the level of water, as the more water, the greater will be the level of solubilization. This will cause the salt to create an extended surface, as opposed to serving as a limited mask suggestive of a chip. Finally, keep in mind that the chipping was around panel lines, and areas of high abrasion, so plan accordingly.
A number of my friends have used the approach on armor, with great success, as conveyed in the article. Brian Barton's pieces are judged in the advanced category at the Armor Modeling and Preservation Society meeting each April, and he usually is given a gold for his salting technique which is highly impressive and well-received.
Best of luck, guys.