Well, the issue with wall griefing is a real problem only at the beginning, when you have just scraped out every possible material to get a pallisade and you just can't afford a ram while sitting inside a griefed wall. At the moment you can build a ram when and where you want it doesn't matter much. But a ram takes 24 hours to dry so anyway this is annoying.
Also if the initial square is big enough to hold 8-12 plots and an idol, the griefing issue is not souch a big problem, because of distances.
But, if you make the spiral so that the outer wall becomes part of individual plots walls, like this
![plan 3.png](./download/file.php?id=1762&sid=ae35520be045b8fd61d336a6c0f4537a)
- plan 3.png (18.62 KiB) Viewed 699 times
that can be quite efficient resource-wise, or at least moving the effort from making initial cornerposts to building rams.
In fact in many medieval towns there were houses built next to an outer wall so there is some similarity in RL.