Wasn't familiar with Oxysolv, so did a little research. It seems to claim that it turns the rust to zinc/phosphate. To do that, it would have to have zinc and phosphorous in it. The phosphorous, would need an activator, so it sounds like part, if not most, of it is phosphoric acid. They claim that it's non toxic, and since phosphoric acid is in most soft drinks (that's what disolves a nail in Coke if you've ever heard that story), and zinc is a mineral common to vitamins, it's probably feasible, but dosage has a lot to do with that.

Naval Jelly, Rust Mort, and most "common" rust removers available to the public contain phosphoic acid. For treating bare steel body parts I buy phosphoric acid straight and make a diluted mix to spray on parts prior to painting.............basically a home brew of Rust Mort without paying for the packaging.

A wipe down with steel wool or a fine scotchbrite pad will probably remove most light surface rust. Make sure to wear chemical resistant gloves and eye protection. Rinse off with water, which could be sprayed and wiped off if the tool or equipment wouldn't take well to flooding with a hose. Sometimes just some elbow grease and a light abrasive pad (again, gold scotchbrite might be enough) is best.

Then coat with a light oil, e.g. ATF, hydraulic oil, or WD40. The WD is easy to apply, but costs more because you're paying for the aerosol, and you'd still end up wiping down the excess.

Don't know about the antifreeze. Sure it's got corrosion inhibitors in it, but it's also water soluble, so over time I would expect the absorbed moisture to promote rust. A lubricating oil, such as ATF, has corrosion inhibitor too, and won't absorb moisture.

Knowing that your shop space is huge this might not be economically feasible, but maybe you should get a (or several) dehumidifier. I keep one running in the shop year round. If it's not doing me any good, at least I feel better about it.

Haven't heard from you in a while. Did you make it on the HGTV show, and are you nearing the end of the make over?