Neo4j Professional: best hw configuration

I just have to install a Neo4j Professional cluster with 3 instances, both in test and both in production.

Which is the best starting option to dimension both kind of machine in an AWS EC2 environment?

How many cores? How much memory?

We don't have a lot of data, we just need to install and configure, maybe migrating later to a larger instance.

Is anyone experienced about this topic?

Thank you