Yacht Vigilant (this is the crest of the hill) - You can see the Big Canyon Reservoir on the left and Fashion Island on the right in the distance.
You can't get to this location, this is now a gated community and public access is denied.
Using the pictures that were taken and noting the fixed structures and the angles, we can triangulate to determine where "X marks the spot"...
The Swing Low was towards the right, looking down the hill (one other hang glider was to our right), most of the other hang gliders were on our left.
This is the general area for the takeoffs at the top of the hill.
Yacht Vindex (Picture #1) - Notice the buildings in the background this is "Fashion Island" in Newport Beach, CA
Yacht Turant/Yacht Coquette (Picture #2) - St. Michaels All Angel Church is on the other side of the reservoir and you can see the angle of the roof.
Yacht Turant/Yacht Camilla (Picture #3)
An onshore wind seems to line up well with the direction of the “Swing Low”
St. Michaels All Angel Church, roof angle