Opposing School Evocation But Still Wants Greater Ruin

[Tekill]

My Wizard build has Evocation as opposition school. I can not confirm what school Greater Ruin is, but I have heard it is Evocation. And, as I understand it, it is still possible to pick Epic Spells even if they are your opposition school. Is this correct?

It terms of my wizards build- My character needs more of a punch in terms of causing damage.
As I understand it, learning an Epic Spell is more like learning a spell like ability than it is learning an actual spell. Having mastered magic in general, you create a seed of magic and turn it into the Epic Spell ability.

This would be instead of the usual way of researching or finding a scroll and trying to study/learn it.

First of all is this generally correct?

Secondly what is the varying opinion on terms of learning/mastering Epic Spell abilities?

I spend a lifetime avoiding a certain school. My character studies Transmutation and Necromancy. Then I decide to master an Epic spell of my opposition school that does positive damage. I do also plan to study an Epic spell from each of my chosen schools first, but is it cheese for my negative energy studying non Evocation wizard, to suddenly want to master a positive energy Evocation type Epic spell?

I can personally see my wizard going, 'okay I have studied all the other schools- lets see what the other side of coin is like' - and then studying an epic spell that is unlike anything he has learned in his past...but would he be able to do it, realistically speaking?

[Valefort]

Technically you can take it.

[Tekill]

Technically