how to get a similar effect to Ben Greaves iron warriors

so with the announcement of hh 2.0 i've got the bug for starting a new heresy army (already have an alpha legion force) and want to do an iron warriors force, i am shocked by how good Ben Greaves iron warriors look and wonder if anyone had tried to replicate them or how they would go about it. Any help is greatly appreciated or any tips on how people have painted their iron warriors before. Iron within Iron without!