Fluid film vs woolwax? Vs hard-on?

Put blob of light grease on a piece of black steel. Let it sit awhile, you'll see the area around it expand as the oils creep long the surface. It my not be thick but it does put a molecular layer between air and the steel.

 

You can brush on Hard-on.
It actually says it's a 'one and done' topcoat and it works better IF some surface rust is left on.
I used it on some new parts and continued with frame and control arms.
This is the 1st winter so it hasn't been on long enough for me to give any input on effectiveness or longevity.