If anyone needs help it's Ulm. And if that advantage is crafting, so be it.

Perhaps the Silver Arm will allow the Smith/Hero to craft items of certain other spheres while not having the magic spheres. I.E. Giving 5 spheres for purposes of crafting to non-earth Spheres.

That would allow them crafting diversity (which Ulm LACKS) but not the spells that are behind it.

Just a thought.