Im not sure we would entertain another tall down back either. With Rotham and possibly Brander as 3rd tall options, what would Williams role be down there? Presumably Barrass or Gov to the bench if Bailey is down back, but that would really make ruck rotations and key backline match ups a nightmare to co-ordinate. I just don't see Bailey ever playing backline to be honest.
In my opinion, the ideal would be to play a defensive seven and have Barrass at full back, the second ruck at CHB and allow McGovern to roam as a marking spare as much as possible.
When Naitanui goes off the ground, McGovern moves to CHB and Rotham or Hurn (or Brander) assumes the role as the floating defensive spare.