So in going through my recently painted Union regiments, finally got to the phase where I'm giving the units their flags.
For the staff finials, I looked at quite a few photos of original union flags that were still attached to their poles, and it seemed that nearly all of them, or at least most of them had spear heads of various styles for both the national and the regimental flags.
In one of Troiani's paintings, I saw him put a spear head on the regimental and an eagle on the national, but in others both flags have the spear head.
The halberd head also shows up here and there.
My question is, was there a regulation regarding what was to be used on either the national or regimental, like designating that only a certain type would be used on the national? Obviously spear heads were used on both. But like for example, would the eagle ONLY be used on the national and never the regimental?
The 28mm sets of metal finals and tassels I got have an even mix of spear heads and eagles, and another set has varying styles of spear heads, so any combination is possible.
Update: I found this image of Don Troiani's depiction of Opdyke's Tigers at the battle of Franklin. It appears to show BOTH the national and regimental with eagle finials. I highly doubt this would be a detail that Troiani would guess at, he must have obtained information about the original flags or saw photos of them or saw them in person, or both: