Actually, Norfolk/Hampton roads is pretty bad too, so you'll be prepared.
I'm not an expert and I don't mean to get you down, but I mean this is southern california you're talking about. Worst case scenario? You don't want to know.
I think that most times if you leave a couple of hours, that should be fine unless there's trouble. Carpool lanes help too. Every once in a while you'll get hung up for longer. There's just nothing you can do about it and you'll get used to it quickly.
From the part of the trip that's north of downtown L.A., figure that this will be bad in the morning headed south and bad in the afternoon headed north. Rush hour starts early and ends late. The opposite is true for the stretch south of L.A.; south will be bad in the afternoon and north will be bad in the morning. Once you get to orange county, it will be bad in the morning and in the afternoon in either direction.
Late August and early September (kids back in school) are particularly brutal I understand.
Weekends shouldn't be too bad.