OK
@cephalo - you are all set. The complete mod package is attached to this post. The PerfectWorld6.lua file included also has the problematic function already deleted. Obviously, feel free to replace that file with your own if there are any other updates you wanted to make or wanted to do the change on your own.
I'll summarize the changes:
I've created new map sizes that are 15% larger in height and 15% larger in width, ensuring that all width and height values are even numbers to avoid any issues. These changes ONLY take into effect when PerfectWorld6 is selected as the map script - nothing is changed if the user picks say, Fractal or anything else. Also, these changes are
totally invisible to the user - the only difference the user will note is that, when PerfectWorld6 is selected, if they hover over the map size for the description, the description text will also have (configured for PerfectWorld6).
I also added support for the most popular modded map sizes (my Larger Map Sizes mod, and Gedemon's YNAMP). I don't think there are any other map size mods out there. Again, these changes are
totally invisible to the user, and these map sizes will only show up when the respective mods are activated.
I also modernized your .modinfo file. You will notice "LoadOrder" on the new actions - LoadOrder is the only way to set mod components to load sooner or later than other components. I gave these actions a high load order to ensure they load after popular mods that update mapsize configurations, like Religion Expanded or Terra Mirabilis.
Let me know if you have any other questions! I'm more than happy to help you further on this, keeping it updated, etc.