Friends, it is very urgent to send 1 letter to 500 addresses.
AmazonSES + DKIM is ready to do this.
AmazonSES capability: 5 emails per second.
How to use PHP + cron to send them? The problem is precisely in the calculation.
I think I sent one letter - wait for usleep (200), then another one and so on until everyone leaves.
Also, in the future, you will need to send one letter to 140,000 addresses, it would also be good to know how to do it correctly. But at the moment the priority is on the first question.