After losing piggies and crops to Greydwarf raids, I felt it was time to build a wall around the entire complex. Since you can’t build walls unless there’s a workbench in range, that meant enough workbenches the outer wall was always in range of one. Which, as a side effect, meant that I have workbenches covering my entire base.

If I was purely going for spawn suppression, I’d suggest torches, since they’re cheap, but workbenches mean I can build anywhere inside the base, instead of just near the main house. Most of the workbenches are exposed to the rain - which hasn’t mattered so far. They’re damaged, but still there.

The size of my base is “big enough to get what I want done.” Which means enough space for a couple of pig pens, a carrot farm, and kiln / smelter setup, in addition to the main house. Mostly it’s the pigs and the carrots that seem vulnerable to Greydwarf attacks.

If you can expect something big, like trolls, I think you need a trench. No wall is going to stand up to those for long.