Kibana Sizing Guide?

[Tomo_M (Tomohiro Mitani)]

The post was from elastic team member. He says it is quite light weight.
I suppose Kibana coexisting in Elasticsearch node could be a good start point.

Kibana server sizing?

It's pretty light weight unless you are using the Reporting functionality (which requires CPU). I'd just use a single CPU, 2GB at most.