Mate check out this site .
http://www.cococs-tourism.cc/water.htmSure you will get enough info here.
We went there last year in about August for 2 weeks, just as private group not with the kiting tour group there that Jen runs.(zephyrkitetours.com.au)
Cocos castaways is a good place to stay and they are all pretty helpful.
Enjoy not sure of exact dates the tradewinds blow but best to check with locals as it changes a little each year.
Enjoy