Norton has some styles that let two bars work as one.
Double the tempo, and use two bars to make one.
It will sound right, but the whole song will look funny.

BAIB isn't a great tool for doing arrangements.

You could do most the work in BAIB then export the midi into another program for final editing.

There's no midi standard for chords, so exporting and trying to import into another program won't work. A program like Sibelius is easy to re-enter the chord names.