Perhaps you are better funded than I was/am, but I would never go out the gate with 5,000 of a flier I'd not tested.
What I mean is, an ad that looks good to you or good to the ad agency who designed it, may not be appealing to your customers at all.
I would be more inclined to have several designs printed in short runs of 100-1000 pieces, being sure to code their contents somehow so you can track performance.
Then, with good tracking, you can see which fliers worked and which ones flopped. Choose the best three and print 5,000 of each.
To save money also, you can also print fliers "2-up," or "4-up," or whatever size your print shop can handle.
For instance, let's say I wanted a total of 5,000 fliers, and my testing indicated that flier A and C did best.
I could print 2,500 of each in two separate runs or I could run them "2-up" on a double-size sheet. So I make one press run, but get 2,500 of A, and 2,500 of B.
If you ever do anything with post cards, you can usually get 8, 12 or 16-up. That means you can print an entire year of monthly post cards in one run.
I have found that if you're not doing your own designing, it's easier to get the print shop that will be printing your order to do it. They will know how many "up" they can do, how much bleed and gripper space they need, which software works best with their system, etc.
I have a large printshop nearby who can also do mass mailings for me, so all I have to do is bring them my art, my mailing list on disk, then I never see the job til one lands in my mailbox (always mail pieces to yourself, and a couple friends/family members to verify the mailing is going out in a timely fashion).
That's all for now.
General Tsao