Using your map David, I shot from just west of the purple dot(west side of field right next to Keller Springs - Dooley Rd.) last year. The angle was not great and the control tower got in the way.
I was thinking of shooting from the south west side of Addison off Lindbergh lane. Here is a link to the thread on the fireworks last year. Near the bottom is a picture from the railroad tracks. I thought this might be a good location.
http://www.texasphotoforum.com/forum...ad.php?t=29778
EDITED: Added link to last year's fireworks thread.