Gregg, I have the "Museum of the Confederacy's Collection" catalog on Civil War flags. They have the largest collection of Confederate flags at their location in Richmond, Va. Just to the left of the Confederate white house on Clay street.
It was interesting that the 12th Ga "Light Artillery" was actually the "Savannah Siege Train Heavy Arillery Battalion"
One of their flags was captured at Saylor's Creek, Virginia April 1865 by the 1st Connecticut Cav.
The flag is a rectangular battle flag, red field, white St.Andrew's Cross, no edging on the cross, no stars. Battle honors stenciled in black ink. The flag measured (32x37 half) with losses.
Have a good night,