Custom Recipe Tab Broken with Caves Enabled

[Faerendipitous]

Apparently a character mod I've been working on for some time has had a persistent issue in which her custom recipe tab doesn't show up in servers where caves are enabled. Now that I have a desktop that can HANDLE caves (kinda) I'm trying to tackle that issue, since I can now self-test. I've been going through forums and other mods trying to figure this out but it takes approximately twelve years for DST to boot up a caves-enabled server so really I think it'd be easier to just... ask. Like for real, as I'm writing this I'm waiting for a test server to generate and the lovely ambient music has looped at least seven times. 

Attached is her modmain, where all the information about the custom crafting tab is. She also has prefabs files for each of six custom items. I know this is a server/client issue, and have seen other people saying that the custom tab code needs to go above a GetWorldSim command. I've looked at other mods with custom tabs that work in caves and have tried to replicate their execution.

So far all I've managed to do was make the crafting bar... longer?? 

Any ideas what I'm doing wrong? 

modmain.lua