While over kill... like heavy heavy overkill... this is the system I use for my walls.

https://steamcommunity.com/sharedfiles/filedetails/?id=2616553274
https://steamcommunity.com/sharedfiles/filedetails/?id=2621478941
https://steamcommunity.com/sharedfiles/filedetails/?id=2621479044

The wood is mostly decoration and to stop pathing onto the lip.. but between the ditch, the lip and the earthwork it is about 6m-8m wide on the outside. The Ditch should be shallow enough to hit a Greydwarf but wide enough a troll can't step over it.

The system is highly scaleable. I've never had to deal with a blob so I can't saw if they can jump up. Trolls can damage the outside but shouldn't be able to hurt much as long as you deal with any stragglers.

My current base is 50-60m wide inside. (which makes it smaller than most historic example... but I'm just one person... I don't need a 120-150m fort/castle) This is not my current one. This is a starter base that is about 30m Diameter

https://steamcommunity.com/sharedfiles/filedetails/?id=2607585103