The original plan was to use Bowden cables for some of the low register notes, but I've since redesigned those to use more robust and stable traditional linkages.

Bowden cable linkages work well on some woodwinds, specifically those made by Wolf or Eppelsheim. However, on those instruments they're used for harmonic vents; tiny keys that are normally held shut by spring action, where the cable linkage only needs to open the key slightly, and which often need to be placed in positions where traditional keywork would be impossible (like on the bocal). For low register notes, the holes are large and on the main bore, most keys are open by default and must be closed a precise amount for proper sealing, and even those that are closed by default need to be opened a precise amount for proper intonation. So in the end I believe Bowden connections are unnecessary for the current design (unless I decide to add an altissimo vent to the bocal).