Lee,
My machine is set up so it feeds from the bottom of the tank, i originally used a filter like in your link but swapped and set it up the way i have it now.
Mike, The filter im using isnt very complicatied, just a filter housing, a nylon mesh filter and a clear cover that screws over the filter. just your standard cartridge filter. Not sure what micron it is, middle of the road i think. Its rated for high flow, and its sold as a pressure washer inline filter. No restrictions from tank to filter as i said, that hose is fine. originally thought the filter couldnt handle the flow that the pump was trying to suck through it but have found out that it should be able to.
EDIT: its 100mesh, dunno what that is in microns.