I mean can I somehow use the tie functionality you mentioned to tie the array that is referenced after it has already been created.

Maybe. Once the memory (array) is populated, you would need to duplicate its contents into the tied array, and then free the array(reference). You'd end up with more free memory, but in the transition, you'd have used more memory to achieve that.

If the api that populates the array allowed you to pass in an array reference, you could pass in a reference to a tied array.

s what I did, with the array de-referencing and duplication not idiomatic? Do most people not do it that way?

Possibly. For small arrays it doesn't really matter. But for arrays of this size, it pays to know how to make best (most economic) use of them