Invite every control to provide an external standpipe with multiple (say 6+) taps offering potable water best sited on the exit route from the control (ie stamping) location, well signed and ideally under (a) light(s) at night.
I thought that, without exception, the volunteers manning the desks (stamping) were both good-humoured and efficient, whatever hour of the day (or night) it was.
Bigger better signs with more reflective arrow-shaped material, please, with a warning arrow (100m) before a turning off (a priority road).
If 'fly-through' videos of the controls have been locally produced: gather, archive and share them in 2023 for the benefit of volunteers and riders alike.