Quickly!!!! Run down to the local grocery store and peruse the selection of nut and snacks that come in the round cans that have a large, pull off top that is made from aluminum. Try not to pull it back too hard so you don't curl it too much. That is enough malleable metal for several tabs. I used to work in a printing plant and the printing plates from large presses is about .010" to .012" thick and a fairly hard aluminum, but is still able to bend quite well. It makes great tabs. You want to be able to bend it, but also have it stay where you put it. My next choice would be for the copper sheet that was mentioned. K&S has copper sheet in there basic material rack I do believe. It will bend easy, and if the airplane lives long enough, copper hardens with age as it oxidizes and will hold the adjustment. As an alternative, once you figure out how much you need to bend it to make your adjustment, you can make a solid balsa wedge of the appropriate size and angle and glue it in place on the trailing edge and then finish like the rest of the wing.
Type at you later,
Dan McEntee