Linothorax vs Quilted linen vs spolas

[Dan Howard]

spolas: khitoniskos bathus skutinos; ho bursinos thorax

"little thick leathern chiton; the leathern thorax"
(skutinos= animal skin generally; bursinos = dressed leather, or alum tawed - the root is connected to shoemaking)

....which goes to show that the word referred originally to "skin/leather garment", and later came to mean "leather T-and-Y corselet/body armour".

I don't think one can be that conclusive. It certainly refers to leather armour but it could be T-Y or scale or lamellar or something else. The only physical evidence of leather we have so far is Macedonian scale and all of the relevant illustrations are ambiguous.