With the normal intake 1/2 npt I just used a Pvc adaptor to 3 or 4 inch. At a yard good store they have a plastic mesh 1/16 use for making imbroady(sp).
For a real large system use the adaptor, the mesh, than a end cap of the same size pvc. Use super glue to stick it, to the pipe.
It also works when you use a vertical piece for the drain, in a tray system.
Don't use panty hose as it will clog in a few days from leaf matter.
On that point panty hose work for a roughing filter on you intake system to pick out bugs
And you thought panty hose were worthless once you remove them from you girlfriend. If I may quote a girlfriend " it keeps the pircks out"