The problem of fort types

[fantasma]

I thought that having cheap fortresses or expensive is part of the nation's setup like what they have in PD. So it's sort of a pro or con for the nation, mostly based on thematic reasons.

Are there any numbers on how many towers a fort has? Or how many arrows/sling stones/whatever else are in the air? High defense forts should have more. And they should have a longer narrow passage, I think.