On the scale aspect, because we go in multiple passes, we break the scope into small enough pieces and then build it back up in a later step. Iirc the largest document I've seen a customer use was over 1k pages.
There are more complex data dependency scenarios where we find that the data that's extracted and combined (e.g. from page 4 and 40), needs to then be further transformed in different ways (e.g. having an evaluation and a clarification outcome at the end). To make these be aligned in value we are soon releasing a feature for what we call derived agents.