paul wheaton wrote: Look at how the rock jacks are stouter, and have less rocks.
Note that all of the fence and rock jacks use ONLY nails from the nail gun.
You have described using the rock jacks when you can't dig into the soil to plant a post deep enough. Since I have areas like that on my property, I may at some point use that concept.
However, I just thought I'd add here that if you live with very wet weather and high winds, you can get what is called "soil creep" where the constant pressure from the prevailing winds will slowly tip the fence at an angle. A line up of these rock jacks providing counter-pressure to the prevailing wind, could be a very useful trick.
By "ONLY nails" are you meaning that never screws or brackets? Or that it simply isn't practical to drill a hole through and use a wooden dowel? Have your people ever tried making a Rock Jack with either mortice and tenon or holes and dowels? It might be time prohibitive, but it would be interesting to know if it would work.