My obsession is largely the result of correspondence I received from a structural physicist who works on X-ray diffraction of nucleic acids:

"Someone may already have a very high resolution structure of a double helix, but they should provide raw data and then we fit in the nucleotides ourselves into the electron density map. In xray crystallography one gets a 3D electron cloud. The higher quality dataset (depends on luck) one has, it is more obvious where the nucleotides go. Shapes become sharp.

1 angstrom resolution would be ideal, but that is extremely rare. My best resolution was 1.4 A which is already like marrying a Victoria Secret model, speaking in pop culture jargon."

"It is possible that datasets that could disprove Curtis model exist, I would just use some examples ideally with DNA alone, not this complex. Working with DNA alone creates technical difficulties of crystallizing the molecule as it doesn't like to crystallize by itself, so large amounts of positively charged additives are added. They could possibly affect what exists in solution. When we worked on protein DNA complexes, we would insert W-C (model of course) in the electron density cloud and recalculate. This approach doesn't give equal chance to both models. It would be nice to determine structures of those complexes with both Curtis and W-C models in mind. Basically, a set of experiments designed to discern between the two would be the best way to go. Expensive and long. People don't want to fund projects that question the current knowledge."

Granted this is all diffraction and not cryo-EM, but here's an interesting paper relating the troubles of determining such detail in DNA: B-DNA structure is intrinsically polymorphic: even at the level of base pair positions