With this interior view of the fence you get a better look at the framing construction used.
The privacy portion uses (3) - horizontal 2" x 4" backrails that are installed just rear of post side center. They are attached to the post with 2" x 4" galvanized brackets.
On top of the upper backrail a 2" x 4" is placed flat side down. There are two vertical 2" xc 4" boards attached to the posts and then a 2" x 4" is used to cap off the topper.
The topper is constructed of 2" x 2" uprights spaced 3" apart with a 1" x 3/4" holding strip on each side. This holding placed at the top and bottom of the 2" x 2" uprights eliminate turning.