Recommended coolant type

For a system with soldered copper radiator or heater, the best protection package is in the traditional coolant. It is generally sold here (US) as Conventional Green. Do not confuse it with "Universal" Green, which is a HOAT. HOAT = Hybrid Organic Acid Technology.

Yes you can run water, but with an anti-corrosion additive package and water pump lubricant. Check with the manufacturer for the best type of water to go with their product. Justice Bros is one of several companies with such products. @autoxcuda can tell you more about what they offer.

The glycols themselves do not add protection, and in fact can be more aggressive than plain water. All manufacturers including Evans, have anti-corrosion packages in their products. Copper and solder haven't been a concern for the newer OAT and HOAT protected antifreezes for obvious reasons.

One advantage of the inorganic corrosion inhibitors is that it provides protection almost immediately. On an open or partially open cooling system (drip tube or catch can) the top of the radiator is exposed to air every time the engine cools. Another advantage to using conventional green with a copper radiator.