We failed a weapon at our last practice recently due to thin striking surface on a single edged weapon. It was about as think as the core, the sideing's on the front and back were a little bulkier.
This is the best picture i can find on the weapon. Its the 2nd Smaller one. I personally dont find a problem with the thiner striking surface.
It didnt fail for any other reason. Pommel was fine, couldnt fell core through the Cap. Sidings were fine also. The blade was had 3 layers, 4 in some places to give it the curved look. The reason it failed was for thin striking.
Also this is an older picture of the weapons. Changes have been made to them, but this is the best picture i can find without them covered.
EDIT: It wasnt put to the hit test due to being failed for the thin striking. We dont bother testing them if we notice one thing to fail them.
EDIT: At Bo. It wasnt checked by the template because the Thin Striking Surface was so thin. Im guessing its about an Inch or so.