Needing to install a 24 foot horizontal board privacy "wall", we sunk one 6"corner Superspike and three more 4" Superspikes. The fence will be in two 12' sections. Our problem is that with uneven ground, the spikes are not all level with each other creating a difference of about 3 inches from one end to the other (this is the slope of the ground). How can we remedy this? should we compensate for the slope by driving three spikes consecutively 1, 2 and 3 inches deeper to make them level? We are also on sandy soil in Southern Ontario, and wonder about the overall stability of Superspikes when the ground freezes and windy conditions.
For a trivial difference like 3" (large sections of my boundary have at least 3' difference over 24'), I just wouldn't worry about it. 3" in 24' is 1:96,
so nobody will notice that the posts aren't quite vertical. so put the posts in vertically, and then tweak the panels slightly so that they aren't quite square.
If you want to be really precise about it, sinking the fence into the ground is probably the best approach.
For a larger difference, you would need to staircase the fence, probably with shorter sections (to minimize the difference over each section).