Maybe both, but forget the black braunsweig shako.
1.- the sacred band was anhiliated at the battle of Dragatsani. Only very few survived. As far as I know there is only one (officer's) uniform survived to this date, I think in benaki museum.
2.- the First regular army uniform (of what you call as Tarella regiment, from the commander;s name) was indeed black. I was not able to find out whether it was a short jacket or a long coat. Unfortunately there is no exact description anywhere, in my sources (I admit mainly secondary sources). I do not know both of your images and I would be happy to have copies in my email.
3.- Since the First batch of uniforms was short (the rifles were abt 300) I can assume that members of this regiment were dressed at what surplus material the suppliers brought in Greece, or at what surplus material was bought by individuals, before their arrival in Greece.
4.- In this sense I would recommend to you to use both short jackets and long coats at your taste. As there is no evidence of black fezes (apart the "High" fez" or peakless shako of the sacred band) fezes should be red.
Anyhow this regiment was disbanded immediately after Peta battle and had no other participation in GWI.
The next uniform of the regular GWI units was the traditional Greek dress with fustanella etc.
goes to sea with the Terrain Mat.
