Usually. Once you are allowed in the wait is only about 30 minutes or less. If you are there for the openeing you can get into DCA and get your WoC before DCA is fully open. This could take away from DL time.
If you delay you may get a worse ticket or no ticket. They are given out Blue, Yellow then Red viewing zones. Generally Blue is considered good viewing, Yellow is good to ok, and Red is ok to poor viewing. But inside each zone are far better and far worse spots.
Disneyland 1951 has provided great information in the WoC Superthread. Here is thier last post.
http://www.disboards.com/showpost.php?p=39090078&postcount=62
Note that on weekdays in slow season there is one show, on weekends there are two and in peak season a third show.