I have a roughly 3" work height, and my enclosure is 60cm (approx 24") high on the inside. My Z tubes are 30cm long, could probably be smaller for my max work height. Also, I have around 10cm of space left for a vac hose to swing around above the Z stepper.
Here are some details of my enclosure: Advice about enclosure.
If you’re worried about noise, and you want to use a vacuum (highly recommended), then you probably want to consider sound proofing your vacuum too. (Or, build a cyclone and use a much quieter house hold vacuum cleaner.)