If you use Zerex G-05 antifreeze, which is the same formulation as MB brand in 50-70 percent concentration you don't need any supplemental additives.

Zerex G-05 is a carefully blended HOAT ethylene glycol based antifreeze that has all the anti-corrosion and other chemicals necessary for cooling system performance and longevity. It's OE on all current Ford and DC products and is the generally accepted/recommended replacement for "green" antifreeze for those cars that had green antifreeze as OE.

Water wetter an other additives may have value when running straight water, which many race cars do, but the solution is usually drained after every race.

Unless you are a chemist or cooling system engineer or know same and can be absolutely positive that some additive is chemically compatible with your antifreeze inhibitor package, then I recommend avoiding them just as I recommend avoiding additives to any other proper specification automomotive fluid.

As far as vintage models are concerned, most fluids have been upgraded over the years and current specification fluids are superior to 30+ years ago. I would not use a 30 year old antifreeze/additive specfication any more than I would use a 30-year old API SD spec motor oil.

Duke