what? she was doing a form of crystallography that ONLY makes sense if it's a helix? Like, any time you are doing fiber diffraction it's pretty much "a helix". Who claimed she didn't realize it was a helix? I thought the claim was that she didn't recognize the significance of the helical parameters, which of course she couldn't, she wasn't a chemist and didn't have a model in mind with knowable parameters.

She might have measured those parameters, but she still didn't know what she had (as evidenced by how she subsequently spent a ton of time on Z-dna)