Here is a very well made guide by one of my long time friend on Aika Global. This guide contains many useful information such as quest details and even REINFORCEMENT guide. This is extremely helpful, all you need to do is find your class then select your weapon/armour you want to reinforce then it will give you the percentage of which your reinforcement will succeed. Also contains other information such as items and recipe requirements. The good thing is that this database is still being updated even with the new EPICII contents. This also has an Aika NA version in it.

Aika Database

Edit*= 28/12/2011
seems like an error has occurred but rest assured that the owner will be fixing it soon.