Hi Guys !
I'm belgian pyrotechnician and often get in contact with french pyro crew ! Well, just to answer to your question in relation with the shoot site, you'll find 2 screen of the different place where fireworks are shot !
First, you were right, you'll find the "big shell" area > Follow this link:
http://nsm05.casimages.com/img/2011/10/10/1110100407381297578878431.jpg
This area is not often used! During the season, they will probably use it for New year Eve or press event birthday celebration and 14 of july !
When fireworks are shot, Fantasyland and adventureland are closed at 22h: so the people have around 1 hour to finish the attraction and to go to main street to see the show. This is the secure area you mentionned !
After that, follow this link, where you'll find two areas, at the left and the right of the castle.
http://nsm05.casimages.com/img/2011/10/10/1110100407431297578878432.jpg
On this screen, you'll find the two bridges on the roof of Fantasyland buildings where most of the products are shoot during the year.
Due to the neighborhood, DLRP don't have the right to shoot loud fireworks. They have to be as silent as possible ! So... you will not often find a products that is over 3" or 2" !
Just to illustrate: NYE 2011: a french friend told me that the maximum size of the shell used was 3" ! (While WDW use 10 or maybe 12" shell ! ) Funny! No?
You'll find monoshot effets, comets effets, cake with silent effets, and so on !
Sorry for my english, i wanted to share this with you ;-)