In The Colour of Magic, it is shown there is a net on the edge of the Disc when
Rincewind and Twoflower almost fall off the edge.
How big is this net? In The Light Fantastic on page 13 it mentions ships falling off the world, so I guess it isn’t complete.
This is not a duplicate. The Circumfence is one object within the Disc, and I am asking how much of the Disc it covers, rather than just the size of the Disc.