Is "Not enough of these objects were available" correct, or should it be "was available"? I think the former sounds correct, but if I omit "of these objects" then I tend towards "was".
In general, "enough" is used countably with countable objects and uncountably with uncountable objects.
Are there enough teaspoons?
Is there enough sugar?
Q: Do we have a sufficient amount of cement?
A: Yes, there is enough for the whole patio.
Q: There are lots of people coming. How are we for wineglasses?
A: There are enough to go around.
You may occasionally see an apparent exception but this can be explained by the underlying grammar.