What is the recommended configuration on "replication.factor" and "min.insync.replicas"?

If I have a cluster with 6 brokers and on my producer configuration I’ve set “acks” to “1”:
What is the recommended configuration on “replication.factor” and “min.insync.replicas”?

I’ve thought:
replication.factor: “4”
min.insync.replicas: “1”
Is correct this configuration? Can I have issues with this configuration?

And if I have 6 brokes and I set “acks” to “all”, what is the recommended configuration on “replication.factor” and “min.insync.replicas”?

What do you recommend me to do? acks=1 or acks=all?

I have 4 millions messages per hour, and I want to achieve load balancing and scalability, 6 brokers is better than 3 brokers for load balancing?

Thank you so much