When looking at the config file for this mod it references that you can change rates and weights on the loot table... but It seems that neither I nor others have been able to find one we can access

You can use a ResourcePack to alter Loot Tables, just as you would with vanilla loot tables :)

If you´re to make the changes for a modpack you´re creating, using something like Open Loader, might be a good option for you - as it allows the changes to be automatically applied to every world/save.