Sounds a great sleeve idea.

I would just suggest a couple of things;

If you get a Japanese dragon I would go for Japanese characters rather than Chinese, and Chinese characters with a Chinese dragon.

Also do not just choose the characters straight off the wall. I have several friends who are fluent in Chinese and Japanese and when they visted a few studios with me they told me that the characters were actually incorrect.

Best to get the characters researched before you apply.

As a filler you could go with the elements of earth (flowers) wind (clouds) water and fire as a background that joins the sleeve up.

Just tossing ideas around on that.

Good luck with the tattoo and can’t wait to see it when done.

Matthew