Must say never had success with this using an automated approach. In the end always ended up using in cash terms more expert resource than cheaper eye ball resource.
The problem with the last project where I saw this tried was the environment and application changes just came too quickly to gain from unchanged repeated testingtesting; despite the client thinking the system was not very volatile.
If I had many sites with lots of static display I might try a hybrid approach with high level automation to create a target issue list. But I wouldn’t set my sights very high.