We were told that there will be no central obstruction, and today I found pictures of the filter from their website:
Yes, there's no central obstruction, but there *are* obstructions. Of course, this is kind of expected for the bigger models, however, this is not what I have expected before.
Having said that, their 50mm filter seems a real winner in terms of uniform illumination and bandpass, and it is a huge step ahead of competitions. Without the obstruction, the contrast is way better as well. And for the bigger filter models, we shall wait and see.