You might want to check out Joseph Chance's book "the Second Texas Infantry-from Shiloh to Vicksburg" Eakin Press, 1995 There is also a memoir that was written by Ralph K. Smith on the Second Texas. It was reprinted a number of years ago, and I have not checked to see if it is available. Chance's book is still in print.
Runnels is Runnels and not Reynolds. He was the son of Mississippi governor Hiram George Runnels, and a cousin to the Texas Governor Runnels.