I don't blame you for not reading it all, Jack, KS and MD are defined thus
MD stands for Modal Determinant, the keynote of each harmonia. KS presumed that the ancient Greek scales were octave segments of the subhharmonic series, and in the diatonic genus, they could be taken
as segments of one continuous scale analogous to that of the Changeless System and as white-key modes of the Dorian scale. Rather confusingly, they could also be taken on the same keynote.

Well, that's all clear then!