Hopefully the loading times will be shorter now, as I have believe I have succesfully followed the advice given to me by Senshi.
That battle was actually a lot closer then it looks. I intended to roleplay the battle and just charge Helenos at the closest enemies while the infantry just stood by and watched. In fact I was kinda hoping that Helenos would die and I would lose the city. But no deal, the AI was way to stupid for that to happen. Not only did it refuse to use half of its force until the moments before the entire army routed, their general keept doing suicidal charges and they left their skirmishers unprotected at every turn.
Stupid AI.