Some questions about similar Great Works

[Urloc the Great]

Grand Fortress vs Great Wall, under specific circumstances:

I've recently stumbled upon this post https://forum.paradoxplaza.com/forum/threads/the-futility-of-grand-fortresses.1174916/
and it very much prefers the Great Wall GW over the Grand Fortress GW (more siege defense, more troops for all holdings in province)

However I currently have the specific circumstance that I neither use my own levies, nor is my capital in immediate threat of invasion. (Germanic reformed with Warmongering, capital in the de jure Kingdom of Sweden)

Is the Great Wall still stronger in that circumstance? The Grand Fortress would supply me with Zweihanders, the duelling room and the vault (although that would be rather useless, since my capital is in no threat of raiders) which the Great Wall can't do.


University vs Library:

When/where is it smarter to build a Library over an University? I'm still not familiar with how techspread works.


Harbor vs Lighthouse:

Is the Lighthouse just a weaker version of the Harbor?

 

[Aardvark Bellay]

Doesn't the Great Works page on theWiki answer all that ?

Great works - Crusader Kings II Wiki

ck2.paradoxwikis.com

My attempts of an answer..

1) As you more or less said, GW is about local defense and levies, GF is about..well all the other stuff.

2) As far as i recalled and see right now Library is rather for local spread, while university is more about tech points creation

3) Harbor is about finance, Lighthouse for treasure chamber and Royal apartments (shag it baby !), basically.

 

[majdavlk]

not much reason to build anything besides harbor, underground city and great walls