The double helix (dna strand) I personally think could have been pulled off much better. I think it should have used the magic in three's, specifically in this case six
Now with using these (to lazy to color) as nucleotides it will add to the current set of empty spaces in between.
This model goes one full rotation, You can tell by the placement of the nucleotides.
If you would like to view the model ingame heres the save. Feel free to use it and cut it off to the needed size. If it needs to be a certain width then there is no help there!