Clean the washer and the drain plug and inspect them. If there are no scratches or flaws - reuse the washer. I reused mine probably 4 or 5 times without losing a drop of oil.
Make sure you wipe off the filter mating surface and the surface where the drain plug seats so you don't have any carbuncles on there when you go back together.
.03 gallons is 3.84 ounces. Fill the oil filter 1/2 to 3/4 full before you install it, then add 4 quarts of oil to the crankcase and you should be fine.
I don't know how you torque anything without having a torque wrench... but I do know over-torquing steel fasteners/drain plugs into aluminum castings will make your eyes and your wallet weep.
