I haven't worked as a production shop for years. And I haven't changed my materials for quite a while. But, materials aside, I have some procedure suggestions.
One of the first rules is, the more thoroughly you do one step, the less time the next step will take. Within reason. Theoretically, if you can metal finish a dent repair, you can skip all the filling and surfacer steps, and go straight to paint. That's the general idea anyway.
When it comes to the last steps before 2k primer, I suggest being especially thorough. Polyester body filler hardens quicker than urethane. So, an extra skim coat and a careful shaping can cut way down on the amount of 2k urethane primer/surfacer needed, and the time it needs to cure.