Suggestions for ELK instll

Hello team ,

We have to install ELK stack on our infrastructure, separated in 2 sites with 3 nodes for each one .
we will implement the clustering method betwen sites, actif/passif node .

Q : did you know any best configurations of settings in elastic / logstash .. ? (indexation,, shards rate.. refresh_interval) ?

any suggestions are welcome

Regards