Like other aspects of supply, how many NFTs to drop and how many artists to feature is all a matter of demand. If you can justify it, and the artist you are curating only does 1 drop in a year, it is probably ok to drop a lot of NFTs in a single drop, especially if you have a lot of buyers lined up for that drop.
But if the artist drops frequently, on a number of different platforms, then you should work with them to do a smaller collection.