Inside the Perimeter and outside the Perimeter should never share one campaign budget
The two halves of this market have different product, different pricing and different buyers, and averaging them hides which one is working.
Intown, an occupier is weighing an office near the BeltLine against one in Midtown, and the conversation is about talent and walkability. Outside I-285, the same size requirement is a decision about parking ratio, commute from the north suburbs and rent.
Run them separately. Separate campaigns, separate budgets, separate landing pages. A blended cost per inquiry across both tells you nothing you can act on, because the two sides rarely perform alike.
Inside each half, split further by corridor rather than by a circle around your office. Cobb and Gwinnett are both outside the Perimeter and they do not compete for the same tenant.
Set geography by drive time your team can actually cover. Buying clicks in a county nobody will drive to on a Tuesday afternoon is buying inquiries no broker on your team will work.