Amsoil makes a good rust proofing spray.
In my CPC research, I was only interested in actual long term tests, and an analysis of the chemical composition. If it washes off easily, and/or is just thickened lanolin, not so interested. The litmus test was then actual use on vehicles, in salt and sand conditions along with demonstrated panel creep in warm weather etc. Mike Sanders grease is something I also use, but the whole 120C application process is a real PITA, and panel creep requires higher temps. The higher application temps means though that it does not wash off at normal temps. I use Woolwax on my snowblower for summer storage, but that's about it.
I've yet to see a vehicle in our area with zero rust, so how a product performs over existing corrosion is very important. Even a new vehicle will take rock hits on the undercarriage and how the product both heals and arrests rust is another major consideration on long term vehicles. If you're leasing, none of this applies
Noxudol does require a few days to set up, but once there, the much easier application along with known additive packages make it my goto product now.
Toyota, Subaru, Isuzu etc. must have thought so to, as that is what they spec it specifically in numerous TSB recall docs. I also think that having one product that has high mobility/creep for panels, but also can withstand exposed chassis conditions is pretty much impossible...this is where most coating systems fail IMHO.
Every one of the OEM TSBs I've reviewed, where chassis/frame treatment was required, used two products. One product for inside frame rails/body panels (thinner, higher creep), and a heavier body product for external exposed chassis. The franchise rust shops just don't do a good job in the time frame allotted, and the product they typically use just washes off after even a short drive in rain...complete waste of time/money IMHO.