Here is the link to the international specifications for climbing walls.
With lead walls 10-12 metres can be ok for regional facilities but not ideal for any national event and not suitable to run international events.
Climbs is different from most sports in that the SQM of floor space can be modest, and potentially can be put into a shared facility with other sports. Wall space, wall shape, height including over hangs and roof area all important. Lead facilities needs to be able to be serviced by scissor lifts.
Competition Judge training material thanks to Auckland Climbing Club available here.
IFSC Officials Resources: https://www.ifsc-climbing.org/index.php/world-competition/rules/2-uncategorised/59-officials-resources
Current rules and recent amendments are available on this IFSC web page.
IFSC Competition rules and regulations (V1.7.6 dated 06/05/2021)