I do remember I only got one bottle of antifreeze. I mixed some in a separate container 50/50 and THEN I poured it in the car. Little by little until full.
As far as the brand, well... I think everyboyd will have a separate opinion on this subject (just like synthetic or dyno oil). I used valvoline 5 years? antifreeze. It works for me. Just change regularly.
By the way, do not forget to empty the engine block at the same time. There is a plug under the exhaust manifold, towards the rear, you probably will need to get to it from under the car.
Good luck!

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J.H.
'86 300E