get the hepa top 0.5 micron
I found the 'cyclone' I lost too much pressure, so I just go direct into the bag
http://www.amazon.com/708626RCK-Hors...6501361&sr=8-2
I also just run a heay duty hose to the machine I am using. Moving from machine to machine. No ductwork.
I clean the hepa filter, every six months. with a shop vac outside.
The rib ticklers don't get it all.