Step 2: Drawing the Shape
The width of the middle fold where it will not be cut, is 2", and after making about 20 of these I think you should stick with 2".
The rectangle in the middle is exactly 1.5" tall and .5" wide which is the same size of the speaker of the iPad2.
From the speaker I tapered the stem down to just one inch and then rounded the final 3/16" so it would be easy to insert.
Step 3: Almost Done
Step 4: Looking Good! How should you tape it?
There is also another way to cut it that allows for folding and unfolding it without any tape.