I am glad that we can apply Q1 visa. Please advise me the supporting documents for a family reunion Q1.

Following documents are required:
1. An invitation letter issued by a Chinese citizen or a foreign citizen with a Chinese permanent residence permit who lives in China.
2. Photocopy of Chinese ID of the inviting individual or foreign passport and permanent residence permit
3. Original and photocopy of certification (marriage certificate or birth certificate)

I am going to stay with my wife from November until the end of April.

Do I need to provide source of income? If so, can I just mention it or do I have to show a bank letter?

Also, can I buy only one way ticket?

Jason, if you want to apply for family reunion Q type from the CVASC in your country, you don't have to provide bank account for that. You could buy only one way ticket, I suppose.