It is a lot of magnet' holding dust port on internet, mine slightly different - magnet hole closed with 0.2mm membrane. Easy to print, no glue needed. I would recommend two 10 by 2.5mm magnets. On Amazon all neodium magnets much weaker that from McMaster or LeeValley. But buying from later places - much more expensive.

Fusion 360 file for any adjustment, if you wish.