I recommend staying with the original formulation, which is commercially available as Zerex G-05. I don't know anything about the new "blue" coolant, but I know that the HOAT formulation of G-05 offers better corrosion protection for solder than many modern formulation. especially the OAT types.

I'm not sure of the heater core construction on 201s, but if it's soldered copper/brass, stick with G-05.

It's easy to change. Open the radiator drain that has a nipple for a hose, and turn the block drain under the exhaust manifold a half to full turn CCW to open it up. it also has a nipple for a hose, so you can do the job without stilling a drop.

If the coolant is clean and you can reasonably believe that it's been flushed every five years or so there's no need to do a water flush or use any kind of cooling system cleaner.

Duke