My rivers are 10cm wide, but I plan to have some twice a wide in future, so the design had to be flexible enough to reflect that.
The width was determined by that of the average German army truck, and that of horse drawn artillery.
For the whole story of how this was constructed, look here: http://gungnir52.blogspot.com/2020/04/g ... rucke.html
Spoiler: kebab skewers and coffee stirrers were massacred.
