QtPyVCP + NGCGUI??

I am guessing that it's not possible to integrate something similar to NGCGUI into QtPyVCP / probe basic for simple subroutines?

is the only way to create a screen UI and associated py file as per the conversational gcode examples?

you can write all the subroutine you would like, all the probing subroutines are int he subroutine folder along with touch off and the atc remapped subroutines.  you simply write and name and can call b y name in mdi.  if you want to add user interface type like the conversational, that can be done with py or with subroutines, there are many examples of both in probe basic if you have the dev version.  the lathe gui has macro type conversational and mill is as you saw done with py files.  hope this helps!  would be great to have some more contributors to the conversational stuff!