Spell Paths

[upsilon]

I've gathered a small amount of information about spell paths from the tomes and ledgers and such I've come across in spell shops, but not enough to really have a clear understanding of the significance of atunement, repulsion, and denial. From what ive gathered, the more frequently you use some spell in a path, the 'better' all of the spells in that path become. And I know denial keeps you from casting the spells in that path at all.

What I really don't know, is what specifically gets 'better' about them, and what effect attunement has on them. Does having two items attuned to the spell path make it twice as good? does attunement cancel out repulsion? Can you follow more than one spell path? Are the effects significant enough to matter in most cases?