Questions about spells

[Fardaza]

First timer to KBTL...playing on normal.

After reading many posts here, I'm concerned that I may have difficulties at end of game because of spells I scribed and lack of crystals.

Here's where I've got so far:

Mage level 10, Att 9, Def 8, Int 13, Leadership 5075, Gold 156K, Rage 40, Mana 53, Order & Distortion at level 3, Chaos at 2. I've done almost all of Darion and Freedom Islands.

Army: 50 inquisitors, 3 cyclops, 84 royal snakes, 96 guardsmen, 24 archmagi.
Zerock is at level 7 and Sleem is at level 5.

My spellbook reads 19/11, and I have 6 crystals left.
Level 3 spells: helplessness, dispel, precision, battle cry, haste, slow, stoneskin, bless, berserk, magic spring, shroud, trap, ghost blade.
Level 2 spells: healing, flaming arrow, fear, poison skull, magic pole axe, magic shackles, pain mirror, hell breath, dragon slayer, invisibility, phantom, fireball, resurrection, fire rain.
Level 1 spells: last hero, plague, gift, book of evil, sacrifice.
Unscribed spell scrolls: dragon arrows, fit of energy, weakness, and 10 loose ones already scribed.

Here's are my questions now.

1) Which of these spells should I have not even bothered to scribe or upgrade?

2) Which of these spells should I upgrade?

3) Are there enough crystals left in the game for me to upgrade necessary spells and spells I haven't even seen yet? I've got the skill that gives crystal discounts up to level 3.

4) Number 3 implies, should I continue or restart with the great suggestions I anticate getting here?

Thanks for reading this long post and for your replies/suggestions.

Fardaza