Spectrogram is limited to 0.7Hz resolution (16k bins at 11k sample rate),
so it had little advantage to have dot longer than 3 seconds.
I'm sure that Spectran will make 10 sec. dot (and even longer) more
interesting.
Theoreticaly you can gain 5.2dB by going from 3 to 10 sec. dot length.

PS : I (and I think several others) never got Spectogram running stable at
5.5kHz sample rate.

73, Rik

Most stations seem to be taking advantage of the faster speed option (3s dots and dashes) but there is an advantage in having 9s dots and dashes so the speed is similar to QRSS but the S/N is better.