My immigration lawyer also told me that sending money was a very good thing to do , It shows for a genuine relation ship , I was also told that the amount was not to matter to much but as long as it was a regular occurrence, I send my wife $400 Australian a month and this is almost equivalent to her monthly wage in China, It makes her life so much easier and gives her the little pleasures in life that she has not had before, She was very against me sending the money to her at first until i told her of what the lawyer said about helping with the visa application.
Keep all records of the transactions as they are the proof you need, Regards from MinYing and John.