Iceberg Method in Fast Production - Practicality and 'Faking' Depth?

Hey everyone, as a Casting Associate, I'm often in early production meetings where we're discussing character backstories and world-building that goes far beyond what's explicitly in the script. The 'Iceberg Method' is often brought up, the idea that you build out 90% of the world unseen, letting that unseen depth inform the 10% we actually see. And I get it, in theory, it’s brilliant for creating rich, believable characters and environments.

However, in the real-world, fast-paced production environment, especially on indie features with tight budgets and even tighter schedules, when does this approach become genuinely impractical or even detrimental? I've seen directors and writers spend so much time on intricate historical documents or family trees that barely get hinted at, and I wonder if that time could be better spent.

So, my real question is this: when is the Iceberg Method not practical for you, and for those times when a full deep-dive isn't feasible, what are your most effective techniques for 'faking' that depth? How do you create the impression of a rich, unseen world without actually building it all out?