Not wanting my ever increasing painting queue to overtake my recent Forgeworld purchases, I started painting up the Magos Dominus with Rad-Cleanser immediately after finishing off the Castellax. I'm not sure of his rules, I am yet to order the (edit: Massacre) book from FW, but hopefully he'll be a bit of fun on the tabletop.
It was a real treat to paint this guy up, even moreinsight gleaned into the Mechanicum aesthetic. Things like the idea that a Magos Dominus needs almost a dozen servo skulls to help him execute his duties.
Cheers
Dave