The max number of characters that map to a single pronunciation So it seems that there is no way to map the Pinyin version of the pronunciation of Chinese words into Chinese characters directly:

If Pinyin (or Other Romanization) can be Translated Back into Chinese Characters

What must be done is, in addition to spelling out the sound of the word in Pinyin, you must select the appropriate character out of a list of characters that match that sound/spelling.

What I'm wondering is, the max number of items that would appear in that list (roughly). For example, say that there are 10 words/characters that are all called yī. Then there are just 10 characters in the list you'd have to select from when typing that in. Maybe there is only 1 matching character, I'm not sure.

Wondering what the rough estimate or scale is of how many character sets map to a single pronunciation. If it's like 5 or 10 max, or 100  or 1000 in some cases. That would be interesting to know.
The Phonology of Standard Chinese by San Duanmu (端木三) has a list of the 15 most common syllables, followed by the number of different characters pronounced that way, not including tones.
yi (106)，ji (93), yu (90),
fu (73),
zhi (72),
li (71),
qi (66),
yuan (64),
xi (64),
jian (61),
shi (58),
wu (55),
wei (53),
ju (51), pi (51）
Tones distribution should be roughly even for the most part  although the book does say that yi4 represents 63 different words.