Part of the delay was laziness about transferring the stream of numbers into notes on Sibelius, which it turns out was solved easily by using the 'seq' object in Max to turn the stream of numbers into a midi file, which could then be opened in Sibelius. Easy!
The other delay was in trying to work out how the notation would work to (a) allow the guitar and piano to be together but drift apart at times, and (b) still allow the ensemble to play over the duet without requiring the players follow the conductor too strictly. The delay was one of those situations where I decided to just let me brain work on it without me (mulling it over sometimes without actually thinking about it too hard), and then some helpful chats with other composers made it fall into place.
I also had to figure out how to generate the drifts between the two instruments. In the end I took the generated stream of numbers and colour coded it to easily show the head motif—pitches 5, 9, 15, 19, 23, which equals E, G#, D, F#, A#: in Ex.1 the head proceeds from darker to lighter shades of orange, non-motif pitches are white—then anywhere there was a partial version of the head I would double it with a complete version. The pink section in ex.1 shows a very incomplete motif in the upper line against a complete one in the lower line. In the score, these two would either literally overlap (one instrument plays the complete version while the other plays the drifted version) or hybridise the lines by working some of the drifted notes into the complete motif.
In hindsight, I could have then started overlapping incomplete (already drifted) versions of the motif against even more drifted versions to take this further, maybe I'll do that later...
|Ex.1: overlapping the head motif to create drifts.|
In the actual realisation, I take more intuitive approach, taking the longer drift sections and sometimes lining them up against more complete motifs, but sometimes distributing the notes differently, transferring some from one instrument into the other. See ex.2, and more significant drifting shown in ex.3.
|Ex.2: showing transformation from generated stream of notes (bottom stave) to guitar/piano.|
|Ex.3 more significant drifts from the original motif.|