Obviously this is an immensely difficult task, even finding logical and short sentences which contains each phoneme (and / or allophone) is tough. I recommend developing software which could auto-fill this task, but that's up to you. Regardless, each sentence would have to be:
- As short as possible, hopefully only contain every phoneme once.
- Not nonsensical
- Spoken by a native speaker
I advise asking the community for help.