Have many questions on the automatic or system/cron jobs that happen as default.

I have read that its not a good idea to send too many emails out at once. We have a million email addresses, so breaking them into smaller groups isnt feasible.

We would like to have a campaign that we carve up by queuing 1000 per hr, 6am to 6pm, Mon-Friday. Or at least some idea how the default queuing works so that we can work around the outbound email and not be seen as surging the ESPs. 

Thoughts?