A few other pinyin points.

Every so often an answer will have the first syllable in neutral tone, eg. mei5miao4, xiong5mao1. It's easy to discard these wrong answers, since 5th tone almost always appears at the end of a word, not the beginning.

Slightly more common is impossible pinyin combinations, like pun, zuai, etc. I'm not sure how complicated the algorithm for matching pinyin initials and finals is, but it could use some fine-tuning.