I have found that they wind up becoming a bit arched with a little bit of use, bending a little bit forward and a little bit upward in the middle. They are also shaped for a little bit of tongue relief, but a more tongue relief shape does start to take hold. So to me, it seems that it’s so soft that while it does lay more across the whole mouth compared to a ported bit, it’s so soft that it isn’t too much for many tongue sensitive horses and the horse can kind of put it where it wants. But there are other bits, including some of the medium to rigid rubber bits that have some more tongue relief built in.
My most tongue sensitive horse went in the Nathe once… and at first he chewed a lot and was trying to figure out the thickness…then, in the canter I could see the lightbulb go off in his head that mom had no brakes, and while we both survived, we went back to his HS Dynamic RS snaffle.