While it would be interesting to play with analog keyswitches, it would depart from the experience of a real sax, where the "half pressed" key is of not much us

While it would be interesting to play with analog keyswitches, it would depart from the experience of a real sax, where the "half pressed" key is of not much use. And it would dramatically increase the complexity of the design. But the full design is published, just in case anyone wants to try :)