Ex:

- I have a Manager profile, and Sales Rep profile.  

- I create a new Layout called Sales Layout, and add a custom field called 'Stage' to that layout

- Under Layout Assignment, I set the 'Sales Layout' as the default for the 'Sales Rep Profile

- I want Sales Reps only to see the 'Stage' field.  Furthermore, whenever a Sales Rep opens a Contact record, it should always open to the 'Sales Layout'.

I tried to do this, but for pre-existing Contacts, the Sales Rep doesn't see the Sales Layout.  They have to manually changing the 'Layout' field to 'Sales Layout'.  I'd like for my sales Reps to have to avoid this step, especially because we have thousands of pre-existing contacts.