I'm glad you figured it out. Unfortunately, I couldn't respond earlier because the itch.io servers were down. You're right, it's not the most user-friendly system for modifications, and I don't think I'll be able to fix it quickly. But I'd love to hear your ideas on how to implement this and make it more user-friendly.
For your information, in v1.1.2, user tables overwrite in-game tables, meaning you can refer to in-game tables from your custom table and vice versa.
I'll attach the tables that are currently in the game.
https://files.catbox.moe/g6xvag.zip