He did not test any commercial products, baahh... youtube videos are a dime a dozen on crap like that.
If your going to paint it ...
wire brush it to the bare metal as best possible then ...
Corroseal 82331 Water-Based Rust Converter -
https://amzn.to/2GZ64FD
and then ...
por-15 -
https://amzn.to/2Lup2bo
and then paint it whatever color you like.
=====
For stuff that is not going to be painted but you need winter protection (eventually wears off in a few months) or for electrical stuffs ....
lectra-shield / marine corrosion inhibitor -
https://amzn.to/2WjHzbn or
https://amzn.to/2GT3qA9 -> Stuff dries with a waxy yellowish tint and hardens a bit, stays on for few months.
======
For stuff you are going to be doing outside for possibly a few weeks like engine work, and you don't want stuff rusting in your driveway or to protect engine block while exposed ...
Corrosion-X 90104 Heavy-Duty -
https://amzn.to/2GSeRIm --> Stuff is similar to cosmoline and stays thick and somewhat wet.
========
If your going to use a penetrating oil to loosen rusty crap --- a fresh 50/50 mix of acetone and dextron-III is the absolute best --- PERIOD. Everything else in inferior, so if that don't do the trick then I suggest you get out a benzine torch and heat it up till it starts to glow red.
-- Those are all well proven products that work and work well on trucks. I use the corrosion-x when working with people here in the driveway during an engine reman. Just ask Mr. Waterloo how well Corrosion-X works in keeping all those nice shiny metal components from inside the engine away from rust during those weeks of heavy rains while his engine was in a thousand pieces and exposed to the elements.
I use the heavy duty marine spray on my truck and spray it down with about 3 - 4 cans about 2 times a year onto all those exposed surfaces that like to rust in winter. Truck has more than a million miles on it and still looks great.
i know a couple guys who use lithium grease spray you find at the truck stops in winter. they will spray the truck down before hitting the salt and ice and it helps a lot too, especially when it comes time to wash the truck. The buildup comes right off, then spray again.