Why not consider the perfect accuracy of the alephma = 1 + aleph0^(-1) that vanishes in continuous ET?
( Virtually any line through the alephma stays further from the center than any known ET )
Who knows? Maybe using subsequent alephs could even produce better accuracy than JI itself?
:-)
Frankly (not to be nasty but only worry about the limit of that race), what is the sense of the ET nanotonality?
I recall one have about 3500 inner cillied cells in the Corti organ (to cover about 10 octaves).