Slitherine

Hello,
How is overcrowding determined? Is there a spesific limit of units you can have behind walls or something? How do you actyally know that you will owercrowd your city defenses? I'm assuming that regional defenses can't overcrowd defenses by themselfs but if you start stacking units behind walls this might happen.

Let's say you put skirmishers in the city for the siege defense bonus. How many units can you have there before it becomes counter productive?

it depends of the frontage of the structure used during siege, so 6-9 extra units are safe, for each 10% more (so less than 1 is 10%), you get +1 as a penalty to the siege dice roll, so extra attrition or outright surrender.