What is the recommended rate limit for sending emails (smtp) per IP (PTR) when mailing?

Question

Email

There is a mail system configured only for sending mail from the project. (postfix+yii2, 11 ptr-ok)
Sending speed and queues are regulated by php application. Now there is a limit of 3 per minute per IP.
What is the allowable limit? We pass all checks (dmarc/dkim/spf) and don't get into spam. But it became not enough.

Answer 1

Time limits are set by servers like mail.ru in order to somehow deal with smart people who imagine that it was they who came up with spiced ham :) On your own server, set some kind of limits ... no, you can of course, but it will be similar to setting yourself limits on spending on the card :)

Answer 2

1 per second you can not take a steam bath
for a ban, the total number of people who got there manually (well, or with an unsuccessful analyzer) is more important, so just follow this parameter