I would near put my house on a middle rotation of Vaughan, Lawrie, Alvaro, Kerr, Faumausili and a bench option for lock either Bird or Fuimaono. Not necessarily in that order. I would go Vaughan and Faumausili to start with Lawrie at lock with Alvaro and Kerr to come on in the prop rotation. Bird to come on as a roving middle to give Lawrie a spell until he gets fit. The reason I would go this way would be for continuity. Vaughan (solid veteran) Faumausili (leg speed, dynamic, young) then Alvaro (solid veteran) Kerr (tall, can find the line, young) same with lock Lawrie (solid defence, runs hard and fast) Bird (Dynamic, game breaker vs tired forwards, to play a similar albeit potentially better role as Radley)