FTB Tweaks overrides normal CraftTweaker script loading, and instead loads scripts based on the packmode, e.g. expert or normal

1. Default packmodes.json file

Packmodes config file lives in modpack/packmodes.json, in your Minecraft instance directory

2. Adding a new packmode

Edit packmodes.json. By default you should see:

{
  "modes": [
    "default"
  ],
  "default": "default"
}

Let's say this pack will have 2 modes - normal and expert, and by default we want normal to be used. The json should look like this:

{
  "modes": [
    "normal",
    "expert"
  ],
  "default": "normal"
}

Now create /modpack/normal/scripts/ and /modpack/expert/scripts/ folders, if they don't exist already. Put your .zs scripts in the scripts folders.

3. Ingame commands

Run /packmode get to display current mode. It should be normal Run /packmode list to display all modes. It should be normal and expert Run /packmode set expert to change the mode to expert (You must be OP to run this command) If the commands don't work, try with /ftb prefix, e.g. /ftb packmode list