The 320 manual suggests that you gob out a large blob of micro and sand it to the right shape. There is an easier way, I believe the photo speaks for itself.

Caution: Do not take a spoon out of the kitchen drawer! Late shall I forget the day my wife couldn´t find her stainless kitchen strainer and then spotted my beautiful new homemade stainless in-tank fuel filters!!! It took a good amount of diplomacy (and a new kitchen strainer!) to get out of that situation alive........