Finding the Right Mood for a Mockumentary

On a recent indie mockumentary shoot, we tried something different to establish the awkward, understated comedic tone: daily 'pre-rehearsals' focused solely on improv and character work, with no blocking or lines. The idea was to let the actors fully inhabit their roles and the mockumentary conceit before we ever touched the script. What worked incredibly well was seeing how certain actors naturally gravitated towards specific levels of discomfort or over-the-topness, which allowed us to adjust dialogue and scene pacing in real-time. What didn't quite land was trying to push actors past their natural comedic inclinations; forcing a deadpan delivery on someone who's inherently more expressive felt clunky and inorganic. We learned that embracing what the actors brought to the table, and subtly guiding it, was far more effective than trying to mold them into a preconceived comedic style. How do others balance steering actors towards a specific genre tone while still allowing for natural performance?