Question about the workflow/design process/tools used by professional database designers
In my experience it varies from one company/situation to the next.

As a dba I loved toad and sql developer because of the ease of use. 

However there are times where you're required to script things using the lowest common denominator. For example writing installation or upgrade scripts that may be delivered to a number of customers. Some may have sophisticated tools others may not. But they all have SQL or PL/SQL.

My advice is do whatever you feel is right for you. Keep focused on your objective. Is the end result more important than how you get there? Or is the quality of your code and learning experience more important?