In my heresies, and travels through Scott's, Hardee's 1855, Gilham's, Hardee's "1861," Hardee's 1862, and Casey's... it can be complicated by what manual the unit being portrayed was researched and documented as using. The more "Units du Jour" one does, the more flip-flopping back and forth one can be exposed to. (The left-shoulder can be seem "weird" until learned, for example)
Or, what one's over-arching organizational (battalion or brigade) structure decides to use.
Or, what one's unit commander or unit decides they want to use.
Or, when I was just a wee lad... in the Pre WWW Era, and reprint era... reproduction 1855 Hardee's was all we could find.. period.
"Ideally," but not always so... remember "Hardee's Rifle and Light Infantry Tactics" in 1855 was designed for riflemen and light infantry/skirmishers armed with M1841 or M1855 Rifles. Hardee rewrote that for "three banders" in 1861.
In gleichem Schritt und Tritt, Curt Schmidt
Not a real Civil War reenactor, I only portray one on boards and fora.
I do not portray a Civil War soldier, I merely interpret one.