I present a new idea of stable and reliable mount for Varia seatpost in Specialized Venge 2019.
https://www.thingiverse.com/thing:4576784?fbclid=IwAR0O_Fn9wlWd65VCquNhckljuWNzyn3IUnWjb9fF7VrnQ64eKjjbI-1Viw4
I like this!
I had this printed and it wasn't an exact fit. I used a dremel to trim the sharp edges and also flattened the curve bit or the adapter.
www.rec-mounts.com/.../