DOR best practices to upload and download

Summary:

Hi,

We want to do bulk load of document of records to each employees (like each employees 20 Documents of different type) through HDL. We want to understand product limitation /best practices for below scenarios

1. What is the maximum number of size(i.e up to how much gb) allotted for document of records in cloud server storage i.e is there any storage size limitation or restriction
2. What is maximum size allowed for single file?
3. Is there any file format restrictions?
4. In a single load how many files we can upload. Like we have around 6k employees. each employee 10 to 20 documents