UE to Rigify FPS Rig problems

I’ve been working on some shooter stuff in Unreal 5 and trying to edit some pre-existing animation in Blender using the UE to Rigify Addon. Third-person stuff works without a hitch because the skeleton uses the base male mannequin. But my first-person skeleton uses a custom skeleton that shrinks to 0,0,0 oblivion whenever I convert. They practically don’t exist anymore. I figured I needed to make a custom template using the documentation supplied by Epic. But even after following their steps, I still end up with the same borked results. Does anyone have any experience with this? Or is there any known documentation with this addon that works with anything regarding unconventional or non-human Skeletons?

Using Unreal Engine 5/ UE to Rigify 1.6.1/ Blender 4.1.1