PMTA and Postfix, how to limit the number of emails?

Question

postfix

How can I limit 1 letter per 3 minutes
What value is responsible for waiting between connections?
in PowerMTA I have the following settings
max-smtp-out 1 # default be nice on concurrent connections
max-msg-per-connection 1 # max 500 mails in one session
max-errors-per-connection 5 # avoid 'too long without data command' error
max-msg-rate 1/m
bounce-upon-no-mx yes # proper mail domains should have mx
assume-delivery-upon-data-termination-timeout yes # avoid duplicate deliveries
smtp-421-means-mx-unavailable yes
smtp-553-means-invalid-mailbox yes
bounce-upon-5xx-greeting true
connect-timeout 1m
smtp-greeting-timeout 5m
data-send-timeout 5m
retry-after 120m # typical greylisting period
bounce-after 3d # default 4d12h
smtp-pattern-list blocking-errors
backoff-max-msg-rate 0/m # send only regular tries during backoff (default unlimited)
backoff-retry-after 1h # retry at least every 20m (default 1h)
backoff-to-normal-after-delivery yes # revert to normal asap (default no)
backoff-to-normal-after 1h # always revert to normal after 1h (default never)

Answer 1

queues