http://www.battleofchampionhill.org/history/cummings.htm
Regarding his discussion of the angle:
"The Rebel line of resistance, at the crest of the hill, formed a right angle. The 34th, 36th, and 39th Georgia, holding the sides of the salient, were short 11 companies - more than a third of their strength. Thus, at the time that the enemy advance to crush the salient, the three Georgia regiments were not in a proper posture to receive the attack."
Footnote: "The 34th, 36th, and 39th Georgia each had three companies serving with Colonel Jackson at the roadblock. A company each from the 34th and 36th Georgia had been detailed to Major Lockett. At this very moment Lockett had these men hard at work building a bridge across Bakers Creek on the Raymond road." [Bearss, Vol. 2, pp. 597-600, and 617]
Surprisingly, we learn that Cummings had taken over command of Stevenson's 3rd Brigade, only a few days prior.
Terry Winschel, Vicksburg Military Park Historian, should have interesting files on Cummings' Brigade and his four regiments in his office.
George Martin