The most economical method is the copy and paste onto the balsa. A large copy at someplace like Staples will cost $15-$20. Then you can cut the plans up, layout the parts on your balsa, and cut them with a scroll saw or band saw. Cut just outside the lines and use a bar sander to final sand to shape. Balsa sands quickly, usually just a few strokes with the bar sander is all it takes.

Small notches are easy to cut with a scroll saw. It doesn't take long to figure it out.

Brad