OK, will do. On their website, the only have "ECO" and "ST" for the Hayes Mag. I'm not sure what ECO stands for but I think "ST" stands for "Standard" with are organic, semi-metallic. It seems the ST is for durability as one retailer states "Compared to the Trickstuff Power pads, their [ST pads] braking power and temperature resistance is somewhat lower." Given how much cheaper the "ECO" models are, my guess is they are "ECOnomical".
Despite these brakes being quiet old, there are a lot of replacement pad options. However, it is hard to know their performance just be reading. There are a lot on Aliexpress and some of them specific the coefficient of friction, which is nice, but can these numbers be trusted and how do they compare to better known brands which don't specific a coefficient of friction.
I have some studying to do to learn about organic, semi-metallic, copper-alloy, copper-free, ceramic, resin, fiberglass, kevlar, and other specs/qualities for brake pads... Hopefully 200mm rotors will make up for any performance deficits of lower performing pads, but this is new territory for me.