Part of the difficulty with tracking troop movements during Battle of Shiloh -- USA and CSA -- results from lack of a standardized time. Although the U.S. Navy (in form of two timberclads) possessed highly accurate Time, no use of that Time was made by the U.S. Army (content with setting watches by "meridian passage" i.e. "high noon.") Probably, Confederate soldiers set their time pieces by meridian passage, too.
It would be possible to "backward engineer" one correct time for actions and movements during Battle of Shiloh... except, allowance would still be necessary for "estimated time" and "fabricated time" (such as "Grant's arrival on Sunday morning at Pittsburg Landing.") Perhaps, a challenge too immense...