Shared or equal (or near equal) parenting is, unfortunately, not the norm. Therefore, anyone seeking it has unique challenges. However, shared parenting can be achieved. This page gives some guidance on how to do that.
Some quick advice:
1. A judge is unlikely to *order* shared parenting, meaning tell the parents that they must share parenting responsibilities equally. They will, however, often sign and endorse shared parenting agreements that parents agree to on their own. So you likely must negotiate for it, or agree to it, on your own terms.
*Why* judges are currently unlikely to order this custody arrangement is discussed in, among other sources, Edward Kruk's work: http://www.psychologytoday.com/experts/edward-kruk-phd
2. In a parenting plan there is no legal need in Georgia for anyone to be called the "primary physical custodian," *except* the child support worksheet. In shared parenting, there is no primary physical custodian, and the law does not require that there be one. Nearly all discussions of the issues assume that there must be a primary physical custodian, but there need not be, except for the child support worksheet.
3. The child support worksheet, however, does currently require that there be a "primary physical custodian." This complicates factors since it attempts to generate financial obligations based on the assumption that one parent has the child(ren) most of the time. And there is no systematic way to deviate from that presumption: schedule E deviations are not determined by any standard method. So there is no standard method to calculate any child support obligations in a 50%-50% custody arrangement. For discussion and guidance, see the economist Mark Rogers: http://rogerseconomics.com/
See also Don Hubin's "How to Calculate Child Support in Shared Parenting":
Since the primary physical custodian tends to receive a financial benefit from having this designation, this might discourage shared parenting: the parent who would receive these funds might resist shared parenting so as to receive this financial benefit. And the parent who is seeking the deviation might be discouraged since, even though she (or he) has her (or his) children 50% of the time, she pays the amount of child support that would be due if she (or he) had the children rarely, e.g., every other weekend. The child support system should readily accommodate shared parenting by developing a systematic way to determine child support in an equal, shared custody arrangement.