[@BlackPanther] Wind has called it quits for the evening so you've got me for right now. We don't actually have a post requirement. The expectation is something along the lines of: Well formulated and expansive. For the most part we like to use Collaborations, gdocs, etc so any of the bigger posts you see with lots of character names on them are usually that. The IC is a pretty good indicator of the post size but again I don't think we've ever turned someone down because of something like that. Essence was my first jump into the advanced section and I turned out mostly okay *eye twitch* so there is no safer place to give it a try. 
 

Okay on the topic of Weather Angels we've never seen one of them successfully pulled off. Which is not to say that you can't give it a go. http://essence-of-the-world.weebly.com/types-of-angels.html This is the little I can provide you personally about them but they tend to be stupendously powerful. The real problem is that they are general muted emotionally and they are land locked. Wind can probably help a little more since the Angels are her babies. And just speculatively: I don't see why they would have to be limited to one form of nature but no doubt the more you add to them the more you ratchet up the characters power. (Not that we mind that sort of thing too much, our PC list includes: a god, an ark angle, a demi god and an semi immortal necromancer.)  

As for the Academy generally no but with the advent of this season the restrictions on admittance have been relaxed a bit. Since Angels cant wield fragments there really isn't a reason for them to be enrolled but if you want to go that route I'm sure we could make it work. Especially given that the Academy has begun to diversify.