Is 'bags/heaps/loads/oodles/stacks of + uncountable noun' always treated as singular?

Solution 1:

I think some of the comments hit on the answer here. The difference is abstract as opposed to concrete. If I say:

Stacks of knowledge are waiting for you in the library.

I mean, that there are actual stacks (concrete) in the library. If I say:

Stacks of knowledge is what I want.

I mean to indicate a non-specific generically large (abstract) amount of knowledge.