Thanks for the link. For me it is mostly about the size of the negative sleeves or more precisely the width. I ordered some out of pergamyn which were supposed to be for 6 frames but they are not, parts of the negative stripe were sticking out of the sleeve, half to a cm more and the stripe would have fitted into the sleeve. On the other hand, the acetate variant is wide enough for 6 frames but does not fit into my binder by 5mm.
I have fitting one by the German company Herma, Fotophan No. 7762, but they are open at the top and not on the side, which opens another can of issues.