Thanks man for this great job !
I tried to see it by myself, to tweak my sounds a little bit, but I can't get this "double" thing you have with the lower octaves of the saw waveform...
This is the lowest C on my A4, with basic "init" saw sound :
And I can't find any note/octave with the thing you posted... how weird.
I double checked many times
But I agree with everything else you wrote !