How to control the visibility of the project management infolets?

Summary:

Which privilege is controlling the visibility of the project management infolets?

We understand by adding seeded 'Project Management Duty' role, or seeded 'Project Manager' role, the user will be able to see the project management infolets. However, these two roles are too powerful to have unexpected and additional functions.

We have customized roles assigned to end users with limited functions. Now we only need the end users to be able to use the project management infolets and has no impact to their normal practice. Except this infolets, we don't want to extend their accesses or current operations. Which privilege or detailed role should we assign to the end users?