[Darwin]

Tom, my recommendation is to cut some strips of regular copy paper (about 20 lb weight) that are about 1/4 inch wide. When you encounter a join, glue a piece of the copy paper to the back of one of the pieces, leaving about 1/8 inch of the copy paper sticking out as the "tab." If the join seam has curves, it will be necessary to cut little triangles out of the new tab to allow it to fit around the curve. In my own practice, when possible (especially on parts that are big flat surfaces) I back the part with 1mm or 2mm cardboard, and use the backing edge to provide the gluing surface. This is especially useful on ship models for building superstructure parts...it not only increases the gluing area, but stiffens up the structure....my infameous 'box within a box' technique. As with most things, the more experience you have making the models, the easier it becomes to tell when a part needs a tab if none are provided.