I'm translating an application with help of an "informal" translator - a Chinese-American staff which seems unsure about some rules I'm trying to understand.
I understand that Chinese uses no spaces, and that Chinese punctuation (except for quotes and dashes?) is full-width (which visually creates spaces after them). However, I'm not sure how to review sentences with numbers or English words. I found this article on the topic, but it seems biased towards SEO or "old rules".
Some examples that I'm unsure of (writing them with monospace font so the space is easier to notice):
输入至少3 个字符以完成搜索。
正在发送到 2 台打印机。
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我们建议您改用本地 app。
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(the # is not optional)此平台不支持 Apple 打印机。
Should any of those cases include spaces? If so, would it be before, after, both? What about the size - should I use a special space character (half-width?), or just "standard English space" would do? Is there any difference between common nouns ("app") and proper nouns?
I understand these are "readable" and "good enough", but since it's a wide range of users we'll be targeting, I want to understand what is, if any, the "gold standard" when mixing in foreign characters.
Semi-related questions that do not answer this fully: