Hi David,
We are happy to hear about your interest in Clarizen.
Via Progress update email, resources can only update %Complete, Actual Effort or Remaining Effort. Email users will not have access to timesheets You can more information here: http://usermanual.clarizen.com/#4-1-7-reporting-progress$Progress%20Reporting%20Methods.
For logging time in timesheets, I would suggest Time and Expense license. As the name implies, these users mainly report time/expense against their activities in formal time/expense sheets making them more accountable for the hours/effort they report. In addition, these users have access to social discussions, and can submit Custom Actions, i.e. submit forms that trigger workflows, such as submitting a helpdesk, PTO, project, change request and more.
See the following articles:
http://usermanual.clarizen.com/#1-5-editions-and-licensing
http://usermanual.clarizen.com/#1-5-1-license-types-explained
For more clarification, I would contact your account executive, he/she will be able to discuss your requirements and suggest best solution accordingly.
All the best,
Diana