Hi Michael,
attached is a photo showing what I mean. The file size is 11meg so I haven't uploaded it.
From the photo you can see the bottle is arrayed along the helix and then subtracted from
the shaft thus giving a faceted result that is the basis to construct a smooth screw.
The bottom of the photo shows the required bottle rotation as it moves along the screw.
If this was just a profile the start and the end profile could be produced by a sweep of
the helix but this does not work for this project.

thanks
Barry