I agree with Geri B and Mckwilter about using the top of the pointed edges of the pinking as the "edge' of the strip.
I do the same as dotti dodge all the time just to give me extra light - have a small lamp that I bought at Ikea for a very small cost that is ultra bright and I place it on the other side of the machine from me. I can direct the beam right to where I am sewing. Sewing black on black is hard whether day or night and I need the extra brightness.