The Warrens 500 - hoard 175, kingdom level 15; Cedric, Anu, Nysha (had them from previous team and forgot to think about possible changing); three weeks of trying.
Team - Luna, Luna, Rabbit, Luna.
Summary - luck, luck, luck
Also, Amanithrax should be the easiest faction to do.
I won with hoard 111 (before medals and deeds) running Mushroom Man/3x Gobtruffle; my brother did the same on hoard 100.
I guess the trick is to survive long enough for two Gobtruffles to collect full mana - after that it is mostly plain sailing.