Originally Posted by dddd

This is why I don't really consider French or Italian freewheels to be "good".
The "skating" is just a matter of the side plates riding smoothly along the tips of the cog's or chainring's teeth, due to a combination of the dimensions of the chain, the sprocket teeth and the sprocket spacing. It happens regardless of sprocket condition and is simply a matter of incompatibility of components.

I just can't get the same level of shifting performance with those Euro freewheels as with the Suntour and Shimano freewheels of the same (pre-1990) era.

Modern chains and old chains have many profound design differences, and like I've said, I choose to use only use modern chain these days and so also use only freewheels that suit that decision.