Hey Bastian!
In general, it is recommended you have no more than two Repeater APs attached to a single Gateway AP. It's also in your best interest to have multiple potential gateway APs so that there is not a single point of failure that would knock all of the repeaters offline.
Further guidelines regarding a Mesh Deployment can be found in the following documentation:
https://documentation.meraki.com/MR/Deployment_Guides/Mesh_Deployment_Guide#Deployment_Consideration...
Let us know if you have any other questions!
-Donovan
~~If you found this post helpful, please give it kudos. If my answer solved your problem, click "accept as solution" so that others can benefit from it.~~
The Meraki ECMS exam is now live! Test your knowledge of Meraki and become an official Cisco Meraki Solutions Specialist. More info on the ECMS exam found
here.For information regarding all of Meraki's training offerings, be sure to check out the
Meraki Learning Hub.