Urgent Spell Questions

[Joonie73]

Hi, I am trying to script all my main commanders (instead of letting the computer do it all--which was what I have been doing pretty much) & I had a few urgent questions regarding the descriptions of spells in Dominions II guide:

1. Plus/minus signs:

Do the plus/minus signs on the spell description mean that the value covered increases or decreases along with the caster's spell level? For instance, if Bone Grinding has a Fatigue Cost of 100-, does that mean it will decrease if the mage has higher death magic level than level 7?

2. Fatigue Cost:

I am still confused about this value. First, is it the case that a mage cannot cast a spell over Fatigue Cost of 100, unless his magic level decreases that number? Second, some spells have Fatigue Cost as high as 300-. Who could ever even come close to casting it? Third, how much does each level decrease Fatigue Cost? Is there a formula?

3. Battlefield spells that affect all units, regardless of friend or foe:

Some spells, again for instance Bone Grinding, affects "all units" on the battlefield. Why then cast it, if it hurts your troops as well as enemy troops? Is this an error on the guide or does it really mean what it says?

4. Gem using spells:

Are these worth it? There seems to be too much micromanagement required to constantly re-supply the mages with gems.