Double breasted or center fastening?

[immortal]

I don't use the Alexander mosaic for reference. There are several archaeologists who do not think that it is the copy of the Greek original mentioned by the Romans, but made much later. For example the cuirass with the shoulder pteryges are clearly a Roman addition, as by the sounds of it is the belt.

There is no doubt that the Alexander mosaic is a copy of a 4th c. BC original - I'd be eager to hear about which details are considered anachronistic, but both the belt and the shoulder pteryges are entirely Hellenistic. For a clear example of a near-contemporary depiction of a Hellenistic cavalryman wearing a belt, see the Alkestas monument, and there are numerous examples of Hellenistic cuirasses with shoulder pteryges. There are myriad other details that are too true to the 4th c. for it to by anything other than a copy.

Actually there is an enormous amount of doubt about this in academic circles. I have spent a lot of time talking to Dr. Stella Miller Collett about this subject. I will find out from her who has published the recent paper that very convincingly argues by dating each of the items portrayed in the mosaic that it was made around 250 years later than previously thought. The style of art is also not particularly Greek.

This is exactly my point; the equipment looks Hellenistic and Roman and matches no Classical or Alexandrian Macedonian depictions or artefacts yet found. The Persian depictions also do not match Achaemenid styles.