The size of the database and the project are strongly specific and depend on a lot of factors e.g. content, users, customizations and etc. (different content types are with different sizes e.g. you can upload an image with large size). That is why we don't provide exact official information.
The system requirements, that are published in our documentation are minimum system requirements, that means these requirements are for empty Sitefinity project.
You could provide us detailed information about your project. What specific content do you have – e.g. how many pages, which content types, how many users, what customization do you want to add and so on.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items