I understand how you feel. I do.
You´re paying for your advertisement to be seen / heard / read / viewed by 40,000 people. And the cost of reaching that many people is sooooo high, that you´re going to add copy points, then add more copy points, and then add even more in order to make sure you say something which will appeal to all of them.
That would be a mistake.I do understand that you´re trying to make the biggest impact with those dollars, but it´s still the wrong thing to do. There is nothing you can say that will appeal to 40,000 out of 40,000 people.
Consider this: if you were able to successfully persuade one half of one percent of those people to come do business with you, you´d come away from this advertising schedule with 200 new customers. If you´re like most businesses, you couldn´t possibly handle 200 new customers — at least, not all at once.
Would you agree that under most circumstances for most businesses, 25 new customers from one advertising schedule would be a phenomenal success? Then stop trying to talk to the other 39,975, and tell those 25 exactly what you can do for them.
Odd, isn´t it? The more you narrow your focus, the stronger your message becomes.
Don´t be afraid to specialize. Don´t be afraid to get very specific in your advertising.