I usually line up around 6:45/7:00. I always request low tables and have never had a problem getting one. I don't ask for specific tables but one time I wanted a table on the end so we wouldn't be super close to the people next to us and we got that. The CMs are always very accommodating.
At 8:00 they walk the people still in the check in area over to the WOC seating.
We leave the check in area once we have our table assignment and go on rides, then go to WOC at 8. It's nice knowing your table is waiting for you! The earlier you arrive the more time you have to eat before the show, but you could show up later than 8 if you wanted to. I go right at 8 because I'm ready to relax, though
Also, you can come and go once you have your table. If anyone needs the bathroom or doesn't feel like sitting there until the show starts.
I'm not sure about checking in at 8 since I've never done that. Maybe somebody else knows.