I'm new to HOI3 FTM and I was wondering what's the optimal number of brigades in a division? What about divisions in corps, corps in armies, armies in army groups, army groups in theatres? What about aviation and navy? Can/should I mix land units with air and navy in same corps/army? What's the best grouping if I also want to keep the outliner organized (ex: I wouldn't want to have a disorganized mix of land and air units in the outliner).
The reason that I'm asking this is because I' starting my first game and I want to setup my OOB as Germany.
I would appreciate if you can also specify the reasons (stacking penalties, etc).