Schokermole breast plate sizing?

[BuzzyBea]

Our mare is in between sizes generally - cob and full.
We bought a Schokermole bridle recently and she needs a full for her nose but everywhere else she is on the tightest hole. Just bought her a racing breastplate (it is the simplest of them all as prefer not to have fussy tack) but the full was too small and that is the largest they do!!
Does anyone know how the jumping breastplate comes up for size or can suggest another simple version?

 

[OrangeAndLemon]

I've just listed a xfull Stübben hunting breastplate on Facebook marketplace because it was too small (for my draft) but not that far off. Would you like me to measure it?

 

[Michen]

I don’t know if it’s coincidence but 2 out of the 3 of this brand of breastplate I’ve owned have snapped... literally the leather has snapped even when fairly new.

Wouldn’t rely on it XC!

I have cob size and would say they are quite small.