Mr. Nolan,
Information on William Vann is rather slim at best, I know he survived the war and returned to Texas, The map of Battle of Kennesaw Mountain ( The Campaign For Atlanta. William R. Scaife) shows the 9th Texas on the right of burnt hickory, and the 66th under Hardee on the left, shows the 9th Texas under Loring, am I mistaken in what I see, an intresting story of the 66th is found in 4 years on the firing line by Nesbit, during a pouring rain at night men of the 66 crawled across the open and captured a good many men and officers and spiked some cannon , this was at the Kennesaw line. also the 66th had a musician that played the French Horn that at night during the battle of Atlanta the yanks would make request for him to play as they lay in the trenches after a day of killing, after the yanks promised not to shoot him he would mount the parapet and play.