Max thread constraint for Services using Datasources

I am reading the excellent "Wrox Professional Oracle WebLogic server", it recommends to always assign all services (Proxz Services in OSB) a Work Manager with Max Thread Contraint = max Connection in Pool for any DS it's using. So far so good.

What I didn't know is that in older ( <12 ) versions of weblogic if you name the MaxthreadConstraint as the Datasource, the max number of threads will adjust automatically to match the Maximum Capacity of the Datasource. This is cool.
In WebLogic 12, you can do this explicitly in the console: