I see. I am also playing around with dust shoes, DIY separators, etc. I went to the conclusion that for my CNc the best is 2-3 stage shop vac LVHP and a hose around 40-50mm, no bigger than 60mm. I have very serious 2.500w 2 stage vacuum cleaner using 42mm hose that sucks very well.

These Chinese separators suffer from design flaws. One thing is that the dust rotates inside but will not go down until i stop the vac. Previously i had Thein Baffle type from a bucket like thing, it was more efficient. Though at that time i did not know to separated the area with a plate so i does not suck back the fine dust floating around.