Question re: Applying for PR as a Spouse of a Japanese National

Question for those of you with experience applying for permanent residency, especially those who are spouses of a Japanese national.

I am in the process of applying for permanent residency. Nine years in Japan. Gainfully self-employed. Financially stable. Have all my documents in order. Married for 21 years to a Japanese national.

Question is regarding the application. I've seen that many applicants have submitted a separate Statement of Reason, but the application only provides two lines to give the reason for applying. In my case it's simply to live out the rest of my life with my wife here in Japan. 

Is it enough to simply provide that as the reason, or is it advisable to submit a separate Statement of Reason?

Likewise, the application provides a brief space to describe employment (self in my case). Should it be enough to simply submit my tax forms indicating my income, or should I provide separate documentation?

Thanks in advance for any guidance!