The heads were the most challeging part, at first made them too big and had to down scale them and make edits so the "base mode" head could fit inside his chest, also gave it a supermode alt version without his mouthplate, like he appears mid transformation in the anime.
I posted the files on cults for sale, you can get the heads or the whole kit bundle:
https://cults3d.com/en/3d-model/game/siege-galaxy-convoy-kit 