Logstash best practice

Sure, but it's not clear to me how you'll utilize both servers (hence my question about load balancing). As opposed to Elasticsearch, Logstash instance don't form clusters.

--> the load balancer is F5 with TCP

If I understand correctly F5 will do the balancing to the 2 clients servers and so I will have highly availability with the logstash also?
Also read this form:

and found that F5 is good for this configuration, Is it correct?