Over the years I've seen numerous old house photos and one one of the things I noticed was that most houses that had picket fences used 1x1 square pickets instead of board pickets.
Here is a picture of a house here in Woodbury that was taken in 1908. At the right of the picture is a square picket fence.
1908, Woodbury, Ga
Another thing I noticed was that a lot of these fences had alternating height pickets. I wanted to do something that would stand out a little so this seemed perfect.
Here are some pictures of alternating height square picket fences that I found while doing my research.
Undated, Bryan Co, Ga
1914, Columbia Co, Ga
1905, Decatur Co, Ga
1890, Dekalb Co, Ga
1909, Emanuel Co, Ga
Undated, Franklin Co, Ga
1898, Hancock Co, Ga
1895, Montgomery Co, Ga
1870-1899, Schley Co, Ga
Every one of the pictures above has the alternating height, square pickets. Also, all the pictures are in the same time-frame of my house.
The one major difference in these fences and mine is the board that runs along the bottom in all of the others. I may add this board to my fence, I haven't decided yet.