Great post Jim.

I run ZEREX Extreme and it's OAT based &
100% phosphate & silicate free. I started with Dex-Cool but that's hard to find anymore. At least here it is. (I have enough Zerex for another change each vehicle & I just did both this spring

)
I dislike the "All makes, all models" mixes with anything coolant (don't get me started!) because it's just a hodge podge of different formulas and is not remotely close 100% phosphate & silicate free. It's probably fine for folks using the old "green" coolant.