The 6mm barbs are the culprit. I tried to 'reform' one of the clamps and changed my drip to a gush,
so that was not the answer. I ended up with 'run of the mill' screw clamps on the 6mm barbs.
And, the nice, fancy euro screw clamps from the shop.............gone.
I guess it makes more sense to buy four 'run of the mill' screw clamps for a buck than to buy one fancy clamp for a Euro. Still......