Focus on the important things first. Such as consistently having new prospects coming into your gateway page at the rate of about 2-4 per day.
You should ask yourself, "How many welcome emails can I send out in a day?"
I would be amazed if anyone wants to send out that many at that 100/day rate, even if they could. Remember: you must support all those people with more contacts via email.
'Quality' should come before 'quantity' when you do your planning.