Some Fire Magic Questions

[tinkthank]

Has anyone ever had experience with the level9 Evocation Spell Flames from Afar (I forget the name, but the one which costs 20 fire gems to cast and is like Fires from Afar, but supposedly better)? I thought it would be like Fires from Afar, only it would wipe out huge armies. But I have cast it 4 times now on an enemy Jotun army, and have ended up killing only 4 units of about 200. I tried with Fires from Afar (level 3 evocation, I think, and only 10 gems) and did more damage. Is this just bad luck, or is the spell just not so great?

What about Fire Storm? I was expecting something like Wrathful Skies, only fire-like. Used this on the battlefield vs. Jotun troops: Jotun nationals, some disspos spirits and some vampires. Tried it only twice (since it costs quite a bit) I got wiped out both times, and lost two arch devils that way. It seemed I hardly harmed anything with the fire storm at all, and the second time it was up for about 20 turns.
I suppose it is not much like Wrathful Skies in that I need to field a huge troop of fire-immune creatures with it? Due to its large cost, I need lots of gems and a creature with a huge amount of fire skill to cast without going dead from fatigue. How do you use it? Do you use it in conjunction with SCs? But then how do you guard your unconscious caster from oncoming hordes? Or do you not use this at all?

Well thanks for your help