Teach me, expert players of Armored Princess

[kcwong]

I'm trying to get a no-loss mage @ impossible... all previous attempts failed.

- In the first I caved and accepted a battle cannot be done without loss
- The second I failed by digging not enough (had to erect walls to save my units), and spending on the wrong units (assassin and archmage, which came at limited supply at this point, leaving not enough for paladins)

In my current game, I have a bit over 15K, but I'm at a loss about which stack to fight next.

Here's some notes about this game:
- I don't want to use save/reload to kite maps (I am not skillful enough anyway)
- I almost cleared Debir, leaving only the heroes. My tiny stack of inquisitors is not sufficient to deal with the fire arrow spell twice, or poison skull once.
- I did all I could on Scarlet Winds.
- On Bolo I managed to kite to the cave once, and kite the amulet inside too. But there's a stack of polar bears that will travel all the way down the narrow passageway.
- On Bolo I had a very hard time fighting anything - barbarians and berserkers travel fast and are too numerous.
- I wonder if getting some attack/defense artifact would help? I only have enough gold to get a few points...

An uploaded save is worth a thousand words... so I uploaded it to Box.net (no need to register, no waiting in queue, just click and download):
Save game

Would you take a look at my save game and give me some hints? Thank you!