When I import a midi file, after selecting the bass instrument (which is always in treble until changed manually), the fretboard could have anywhere from 4 to 7 strings. Is there some way I can manually reset it to 4 strings and have the tabs based on that 4 string layout?
Also is there some way we can manually change the tuning of the strings, so that the tabs are adjusted to match the tuning settings on the bass?
well no, there are features but i don't think they could be usefull for what you need.
you can change the tuning, and string count from menu Track -> Properties.
but, current version, don't support transpositions. ( yes there is an option in development version )
so if you change the tunings, the fret numbers of tablature will not be moved.
Maybe the solution is to create a new bass track and copy the notes into the score manually and then create tabs from that, finally deleting the original track.
Now I at least know where to find the bits I'll need to tweak.