legions of Steel ect

[GrudgeBringer]

When you have spells that 'buff' one unit like 'Legion of Steel' it says that one unit will have its Armour protection raised.

OK....my question is not only on this spell but on others, say regeneration (where 1 unit gets the buff)how do you know which unit will get the spell/buff?

I mean if I have mercs in the front line and a unit of MY infantry next to it along with archers behind it and 1 mage in back, then I would more than likely want my foremost infantry unit to have the Legions buff and not the MAGE.

Is there any way to tell or direct who gets the spell?

Two last questions, if I cast Sermon of Courage ONCE, does that last the whole battle or just that round?

If I cast Legion of Steel twice do I get 2 units with armour raised for the whole battle/one round? Or does it wear off after round one and I have to do it agian and take my chances on which unit it will pick?

Heeeellllppp!!!!