Tactics for playing as the Dwarves.

with light magic, are you planning on casting a lot of spells?) There's usually enough mana for up to 100 in most cases. Cast a few mass buffs (a couple or three) and use other abilities like vengeance/teleport a few times. (36 mana for buffs, and 14 for vengeance, I think 100 is enough). You can also add regeneration. In any case, if the battles involve large creature gains, you don't need to cast spells for too long, although, unless both have high defense and low damage, it depends on the situation.
I prefer learning the Eye skill for evasion.

Leadership with luck and attack, enhanced with runes, is a very powerful combination.
And there's a higher chance that magic increases spell power (I've noticed this with the Imp), while in Haven, magic isn't as important as, for example, in Dungeon.
Well, I'm not sure, I still need to test it thoroughly.
+It's good that if the opponent doesn't have morale-lowering units, you don't need to fully develop leadership due to harmony (which frees up a level).