Still working on what I promised (i.e., groove widths etc in JSON) -- it is not as straightforward as I originally thought, but I am making progress...
In the DSSR output, the classification of a dinucleotide step into 'A', 'B' or 'Z' is based on new scheme. The basic idea is on comparisons to 'reference' structures, even though technically more involved. The details will be reported later.
RNA helices are predominately in A-form, and DSSR targets on RNA users to begin with. However, DSSR also works for DNA where A-, B- and Z-forms all exist. The classification summary would be useful especially when A/B-form transition happens, as in 1tc3.