So I changed numbers just a bit, to have 40% Coral and 30% tropical fish. So far it was enough to provide outcome I wanted - that there is always at least 1 unit of coral present. I will try with overall increased number of spawned things, just out of curiosity. Also the thing you mentioned about monopoly... Most Coral spawned from this Wonder I ever saw was 3, and it is never enough to get monopoly. I mean I'm playing with biggest maps, so there is decent chance for it, as it require many different resource types, so this can indeed be an issue with smaller ones. So perhaps better not change the spawns from your side, it's enough that I can customize it for myself in the code.Let me know what you got. I'm really curious. Maybe these numbers are not the best and some things could be adjusted in new version based on player feedback.
Coral as a Luxury resource can be really powerful if spawned as the only one on the map. Its Monopoly Bonus can be huge advantage if taken early on.
I can block some choices based on the previous results, f.e. if Atoll is spawned, I can limit it to one, and therefore increasing chances for the rest (2/9th, 1/3rd and 4/9th accordingly).
As you can see the maximum number of spawned elements is 5, unless something was around GBR before.
Now that's this, and also I found 2 more issues with World Wonders:
1.Akihabara Electric Town - I could see this Wonder as possible to build and even start the construction, but every time I did, it dissapeared from building queue after one turn passed. Normally wonders dissapear like that when their requirements are not met, but with this one I definitely had 3 village improvements and the dissapearance occured at least 5 times, as I kept trying to start the construction.
2. Curiosity Rover - it has description with requirement of city without water, yet it is not implemented correctly. I am able to start construction it in any city with improved aluminium, including coastal cities and cities with fresh water