Ennealimmal notation and neutral thirds

I was suggesting that we think of notating ennealimmal in terms of
minor thirds/major sixths, but since we've got nominals based on
fifths it occured to me that neutral thirds might be better. This
would also make ennealimmal, in one direction, look like breed:
instead of generators
of 49/40 neutral thirds and 10/7, it would have 49/40 and 27/25, the
latter wrapping around and becoming a period of 1/9 octave. Hence in
one direction we would then have every other step up and down from C
notated in terms of seven nominals plus sharps and flats. Filling this
picture out then becomes a matter of using symbols in some sort of
intelligent way.