Here's my best piece of advice for this or any army.
Take a Battle Standard Bearer and stick him in the middle.
With the current ruleset, Battle Standard Bearers are amazingly useful, allowing you to reroll any Leadership test. I tell you, the number of times this has saved my bacon... And (annoyingly) my opponent's bacon. And the plastic GW model is also really nice! I often think of the Battle Standard Bearer as an inferior character in combat but there's no reason he needs to be and can be tooled up and utilised like any other character. Putting him right next to the general maximises the joint Leadership benefit they provide (though can lead to a dense army that's less intersting to play with).
As I mentioned under the Empire General tactics entry, another option is to have each character protect a different half of the army: Leadership boost for one half, a reroll in the other.