After further reading it seems that the question is no longer relevant.
Starting from yesterday all new kernel drivers have to be signed by the Microsoft through the Hardware Dev Center.
Now I have to figure out what is Hardware Certification and what is Attestation and if I have any chance of either.
All to have driver that we wrote to be loaded on computer we own and fully control.
But the general direction is clear - Microsoft is no longer interested in Windows being open lab or industrial platform.
They want to be Apple. That is, Microsoft always wanted to be Apple, but today they want it more than ever.
Which means that we should seriously consider leaving Windows. Of course, Linux is also a pain, because of GPL,
but, may be, with new Windows signing requirements it's already a lesser pain.