D F Tweedie
A lot of sequencers have a midi data thinning plug-in. In Cubase it's called 'Density.'
I don't know if there is such a beast in BIAB, but you could look to see what midi filtering capabilities it has. Or, you could again pull out a song you'd arranged as a midi file and do the density filtering in another program ... then later import the midi file back into BIAB.
One nice thing about the 'Density' plug-in in Cubase is that it has a slider to reduce (or increase) the number of notes by a percentage. You can then loop a section and keep moving the slider around till it suits your taste. In Cubase you can then 'render' the way the track is sounding with the plug-in to replace the original data with the data generated by the plug-in. Voila!
You could then use this midi file to create a new BIAB style file using the stylemaker wizard. Now you could have two versions of the style, the regular and thinned one, and even link them to make a multistyle so you could use the A&B parts from both style files ... one in the Multistyle version now being C&D parts.
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