Email Throttling



I am in search of a new reseller plan and have a couple of questions regarding emails.

1. Do you throttle email sending and if so, what are the limits for a domain? If they are different depending on the package you choose please indicate.

2. If you throttle emails do you do it by hour or by day or some other metric.

I host a number of small sites for youth sports. Over the course of a day or a month the email traffic is very low. That said, when the executive board emails the membership of an upcoming event or a change in schedule due to inclement weather there is a need to send 600 to 700 emails in a relatively short period of time.