The NEXUS live notation system, the latest product of the Hayden-Kanno collaboration, contrasts with their previous projects which utilised live DSP and synthesis. NEXUS is first discussed in the contexts of a comparison of Kanno's experience of performing solo violin works involving the live generation of music in both the audio and symbolic domains, and the affordances of Common Practice Notation for generative music. As with previous Hay-den-Kanno projects, the main goal is the creation of a musical work which is fluid and spontaneous, both in its global form and specifics of detail, yet maintains a sonic consistency and coherence, but now in the symbolic domain. The implications of performer reading and interpretation for system design are explored. The second half of the paper outlines the main functions of the Max patch, how GMN code is generated for rendering as CPN in IN-Score during the performance, and, of the performer GUI which constrains the stochastic processes underlying the generation of specific musical parameters, general textual characteristics, and global formal shaping. The challenge was to formalize Hayden's compositional procedures so the generated notations retain a musical identity and interest , whilst leaving space for Kanno's interpretative decisions and being technically simple enough to be sight-readable. The uses of the system for hybrid performance and compositional applications are discussed, and some directions for future development.