This addon require CubicChunks version 0.0.938 or higher (https://minecraft.curseforge.com/projects/opencubicchunks), CubicWorldGen version 0.0.54 or higher (https://minecraft.curseforge.com/projects/cubicworldgen) and MinecraftForge 14.23.3.2658 or higher.
This addon allow to generate CustomCubic-type world above and below vanilla range (0-255) for custom world types with CubicChunks enabled.
It is unnecessary to have this addon on client side. Clients without this mod will be able to join a server with this mod installed.
Create new or copy existing CubicWorldGen preset to path <world_save_folder>/data/cubicgen/custom_generator_settings.json. Use any compatible world type with Cubic Chunks feature enabled. You can add preset before creating new world.