You do not want avenger's shield or anything else with a cast time in the tanking macro.
You can not dodge, parry or block while casting a spell with cast time - which is not something you want when tanking.
Split pulling and Holy Shield and Consecration spam and you should be good to go.

If you are using your shaman along the pally, consider getting imp judgement of the crusader, adding another 3% crit fo the party.