Starting point is the zoning dept. The current zoning will dictate how many houses per acre and other constraints for roads, setbacks and allowable sq. ft. within the current zoning. Rezoning is costly but may be worth it to have a product (house) that is in demand but under-represented in your marketplace. Local experience will dictate what consumers in that area are looking for and if demand is being met.
Cost:$75 per sq. ft. is about right for suburban Atlanta. That is for construction costs- not incl. commissions, debt burden, permitting, insurance. Keep in mind that larger builders can go much lower (on cost) based on their volume and operational efficiencies.
Price Per acre: research recent, local, raw land closings of similarly zoned land - same as comp. for SFR.
Development costs: The infrastructure (Storm water, sanitary sewer, water, power and retention pond), curb/gutter, streets are extremely expensive. And eat into buildable sq. ft.. Followed by grading, engineering fees, and lastly bonds with the local municipality to ensure your work is completed to the county's satisfaction.
Sight unseen, Estate lots require the least amount of infrastructure if the zoning and market will allow.
I am willing to help with any other questions you may have, I am a licensed contractor and have looked at a lot of land.