Right on. That is what I do also. Usually just alphabetical stocks though. Check them all out. I live in the frozen Canadian Rockies however and my internet sucks. Therefor your half hour is about 3 hours for me. I can't imagine scanning with high speed internet. We do have an amazing view however.
Finviz- I love the screening tool as well but prefer to click the snapshot tab after screen results generated for a better glimpse (rather than mousing over symbols)