Ok, hopefully the attached one has the proper rotations now.

It assumes the bottle is pointing upwards in the world z axis direction and is positioned around the start point of the helix, and that the helix/cylinder axis has its origin at the world origin and that the helix/cylinder axis direction is the world x axis direction as in Brian's InialFeedScrewTOP01.3dm file from above.

I think it should work ok if you substitute a variable pitch helix in but I did not test that. But it distributes the items by equal distance as traveled along the curve, so with a variable pitch helix trying to use an item count that's related to the number of helix turns won't place items only at the quadrant points of the helix as it would with a regular fixed pitch helix. I don't know if a sparse placement only at quadrant points is desired but it looked like some of the images had that.

- Michael