Well, I looked at the one at Wookpeckers site, and it has a bottom mounted intake at the bottom of a funnel. This would seem to me to cause exactly the problems you state because the air flow would be straight down. I plan on putting my vacuum attachment on one of the bottom corners, thus generating a swirling action. The airflow down thru the hole on the plate should be quite strong, taking most of the dust with it. The swirling action should move the dust down and out. I don't believe the 890 has any openings on the bottom. But I'm in the airport right now so I can't look to be sure.