Philip of Macedonia Illustration

[MeinPanzer]

As the person who did the research for that illustration and wrote the caption, I can shed some light on it........
The illustration was based on Plutarch's description of Iphicrates reforms. Plutarch anachronistically refers to Iphicrates replacing Hoplite "mail" with lighter body armour. Since I knew that Hoplites wore tube-and-yoke corselet, often augmented with scales etc, I had to think of a 'lighter' alternative..........and came up with the quilted linen thorakes.

Cornelius Nepos' Life of Iphicrates, 1:

[Iphicrates] changed the character of their armour (loricarum), giving them linen in place of bronze or chain armour (pro sertis atquae linteas dedit).

I think it's clear that by lightening their armour, he changed it from bronze muscled and scale composite cuirasses to linothorakes, not from linothorakes to something lighter.

The illustration was based on Herodotus' description, Attic pottery depictions of Persians in what appear to be tube-and-yoke quilted corselets and what appears to be a red quilted corselet from the Alexander mosaic.
Since the particular corselet in question is Persian also ( a trophy), I'd have to say you have hit the nail right on the head, Johnny !!!

All we know from the literature is that the cuirass was 2-ply. Since Persians are actually more often shown wearing regular linothorakes than quilted cuirasses, I would think it more likely that the cuirass Alexander took to using was regular.