Adding a second NIC is definitely a solid plan, we do it for our Clustered SQL Servers and clustered anything. My only comment is that I do not find I need to manually add the static route, Windows assigns it automatically when it detects the second NIC, and expects to use it (in your example 11.11.11.x) for anything in its subnet. Of course, if you had manually assigned that permanent Static Route in the past you would have to delete it when you added the second NIC.
Student of SQL and Golf, Master of Neither