I think there is more than one school of thought on running carbs dry prior to storage. If the fuel is treated properly (stabilized) it shouldn't gum anything up and running dry may cause seals, gaskets or whatever to dry out and leak when the car is brought out of storage. In deference to this, I usually ran my carbs dry so I guess that's what my personal preference has been.
As far as "fogging agents" go, I used to do this to my Harleys prior to winter layup. I would spray the fogging oil down the carb throat while running the carb dry, fuel petcock closed. This would allow the engine to run long enough to get pretty smokey and stinky before it quit. The theory is that this oil mist protects the cylinder walls during storage.
My fogging oil, a spray can, was purchased from the Harley dealer, so of course it is probably available elsewhere cheaper.
In East Tennessee, there is no such thing as Winter layup. There were only a few days when I couldn't drive last year, salt ya know. I might have to bundle up due to the lack of heat, but it's still a kick!
John H.