most if not all spells are based on two magical skills instead of one. chain lightning requires a skill of master level of elemental magic and light at normal level. increasing the strength of elemental magiic will cause more damage. i think the light skill will yield greater range.it seems there is a cut off point on benifiting from the secondary skill.
the spell description will tell you how strong the spell is, say you increase a magic skill and notice no increase in the strength of a spell, then you know it is pointless to increase a magic skill for that spell.
