Linothorax vs Quilted linen vs spolas

[Paullus Scipio]

Paul B. wrote:

It seems to me that a design like the T-Y arose because the material was very stiff.

....I suspect that is an over-simplification. The stiffness is likely to be because more than one layer of leather was used ( assuming leather in the first place! ). Recall that in 17C Buff coats which were 'double layer', it was generally only the body which was 'doubled', with sleeves etc left single for ease of movement.
One should also consider other design factors too. Like the 'lorica segmentata' of Rome, the design was optimised to provide protection to the shoulders, logically enough considering the shield offered primary protection to the body from frontal blows, but a spear used overhand might strike a blow over the rim at the shoulder area. In addition, downward hacks with a sword/machaira would be a frequent type of blow in a close press. In addition, any blows from spear/sword which glanced off a helmet would most likely be deflected into the shoulder area...... no surprise that the shoulders were obviously considered a vulnerable area needing special protection, hence the 'yoke'. Add to this the basic simplicity of 'Tube-and-Yoke' and it is no surprise that the design was a popular one for so long, and spread beyond the Greek world......

John Conyard wrote:

The pteruges do stop above the certain important areas........

But they could be shorter. There is a double layer all the way around the bottom of the tube. I want them to comfortably sit over my thighs when on a horse.

You are surely right about this. On the face of it one might wonder why the obviously stiff pteryges do not extend to cover the lower abdomen as for example later Roman ones did, which were clearly softer. A comparison of your photo and vase depictions - even just those posted here - suggests yours are over-long, and need to shortened, especially perhaps for mounted work. Perhaps the originals were this short to facilitate sitting, but it should be borne in mind that like modern Asians, the ancient Greeks were more used to squatting or camp stools, being less accustomed to chairs than us 'moderns' . ( before anyone picks up the point, yes, there is plenty of evidence that Classical Greeks used chairs - but not to the extent we do)