Thanks to Blaze making a player and NPC model, I found what perhaps maybe the only way in posing a giant iron giant perfectly.

First you need to get this from the workshop https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=470366741 When you're in the game spawn in either the playermodel or the NPC model. Use the tool that you downloaded to resize either of those two models to scale 12.30.

Boom, a giant iron giant that is able to be moved perfectly with the ragdoll mover. At first the joints shown when using the ragdoll mover are in odd places, but after hovering your cursor over you'll find the joints.

An odd solution, but it works.

Thank you Blaze for creating the player and NPC model that actually works with the ragdoll mover tool.