with 100 bpa channeling, that's +60% runes.
assuming you're not a mystic, and you're only gonna do lots of self spells, and casting some pitfalls, greed, droughts, vermins and fireballs with your extra mana, how much towers is needed to support this rune consumption?
i was thinking that maybe, 10% would be enough?
i don't really know, that's why i'm asking. have not played a spell caster for a long time.