Representing the 7-limit diamond distinctly

One can represent all of the notes distictly in Meantone[21], the
scale consisting of 21 notes generated by a chain of 20 fifths,
reduced to the octave. This is a minimum value, it appears, though
matched by Augene[21] and Myna[21]. Meantone[21] is a scale of some
classical standing; Mozart, for instance, taught it as the full gamut
of notes.

More accuracy can be obtained from Orwell[23], Magic[25], or
Miracle[27]. Sensi[27] gives a MOS. If you really need accuracy
there's Hemiwuer[33], or the full thermonuclear option of Ennealimmal[63].

Detempering Sensi[27] might be one way of proceeding, if JI is
essential. Partially detempering Myna[21] or Miracle[27] to breed is
another thought.