I've not got one but I did have a look and I think that you need to be careful about the size you order. They definitely seem to be sized more generously than horseware rugs going by the chart anyway. I think the wither to tail measurement is quite interesting as a 6ft3 HW rig is 140cm wither to tail and the 5ft9 Chonma is 139cm.
I have one, a full neck medium weight that I bought either last winter or the winter before, as cheap rugs they're alright, it fit quite nicely and didn't leak. Also fit true to size.
Think it tore relatively easily (I can't remember what denier I bought though) but I still have it as a spare.
So a little update, I won the auction for £27 English pounds, this is for a 1680d 300g turnout! It arrived this morning so less than 48 hours and for the money it's great! I bought a 5'9 which is what my mare takes in shires rugs, it seems well made enough and fits well, big thumbs up from me!