I like your ambition. If I may, I'd like to make a suggestion for the experiment itself, which will help establish controls and make relative comparisons more intuitive/easy.
First, get yourself a stock of steel to use...flat bar or round stock, whichever is handier and cheaper. Flat stock may be easier to show corrosion or inhibition of corrosion than round stock, though. Cut yourself a whole bunch of blanks, say inches long or so, and drill one end so that it may be hung.
Next, make yourself a board to hang a large number of these blanks on. I'd recommend using something like plastic coated cup hooks. Plastic because it avoids metal-to-metal contact with the bars. Cup hooks because hanging a 6 inch blank on a cup hook will keep it suspended in air and not result in it resting against the wood. You can install the wood board such that it hangs out slightly at the top to encourage the steel blanks to hang away from the wood.
Clean your steel blanks to ensure they're bare metal...do the final handling while wearing nitrile gloves to keep finger oils/acids off and do a final wipe down with something like alcohol.
Then coat each blank per the directions for each product you have and carefully hang them on the board. Label by each hook so you know how each was treated. Maybe make a paper chart as well.
Be sure to put one or two untreated blanks on the board as well, so that you can use the corrosion it undergoes as a marker for the effectiveness of the various produces to inhibit corrosion.
You may also consider having a few steel blanks professionally blued, anodized, or whatever, to hang up untreated as further comparison.
Then put the board wherever you intend it to be over the coming months/years.
You may even consider two or more identical boards in different environments (one in the garage, one in the house for example).
Nothing impresses people more than pictures, and a setup like this will show both how controlled the experiment is AND will provide side-by-side evidence/comparison which is very easily illustrated by pictures. Which is why I recommended flat stock over round stock for the blanks.
Keep us posted!