I went a different way for my multiple tourney-winning Word Bearers.
I used the body of the new emperor's champ, one hand in the air with the blade. Lots of potential with that pose. But to get to you original question..
I am in love with the dark apostle pic from the chaos codex, so I decided to make his crozius and most of my model into his likeness. I took the small 8-pointed stars from the chaos vehicle sprue(you will need two), and flattened the major surfaces of the rivets and the center skull motiff. I then cut one cleanly in half and after some snipped and filing, I glued it to the flat sides of the unbroken star to make it look like an X from the top. You will need to remove the snipped star's top and bottom star point, and the bottom of the unclipped star to fit the incoming grip section. Add this mace-top to anything you thing would look good, I used the confessors mace-section, then adhere it to handle with a suitable hilt potruding from the bottom, in which I used the already present hilt of the Imperator Rex from the emperors champ. Before you finish your model, give this method a shot. You might slowly become shocked how great it comes out.
Bjorn