Considering a Hanzi character a square with an aspect ratio of 30:30, the ratio of width to height of its Zhuyin annotation will be set as 15:30. The Zhuyin annotation should stay adjacent to its corresponding base character.
The aspect ratio of initials, medials and finals is 9:9, while that of Mandarin non-neutral tones and dialect non-checked tones is 5:5, that of Mandarin neutral tones is 9:2, and that of dialectal checked tones is 5:5.More details and figures can be found in Positioning of Different Composition for the Tones below.
When the font size of the body is relatively small, it's possible to provide a larger font size for theZhuyin rather than using the default ratio listed above. Alternatively, other methods, such as bracketing Zhuyin inline, are acceptable.