If we had to have a catalogue illustration of every single shape for every pattern before we allowed an attribution, then there would be a lot of "attributions" removed from the glass scene. As I said above, we can see a dresser tray and a covered jar in known catalogues (there were probably other catalogues, etc., but they are not yet known). No manufacturer of the size of Walther is going to have made a single jar and a single dresser tray in that pattern, and have it matched up with items produced by other makers when it was marketed.
The variation to the mermaids' arms could mean several things -
1. possibly there was more than one set in use at any one time (note 2 sticks to a single set would mean it was taking more use per single set)
2. possibly the mould suffered damage and was recut
3. possible one version was hard to get out of the mould so they recut
4. possibly the first version was damaged and when the set was made in the 1950s a new mould was cut for the sticks
Dresser sets known are in matching colours. It makes logical sense that all items in the set were made by the same maker. However, as we don't (yet) have an actual illustration of the sticks, you can simply say "probably Walther" for the sticks if you feel uncomfortable about going the whole way.
Glen