The amount of sesame seeds and peanuts as specified in the recipe are sufficient to pack a 10 in x 6½ in pan. The melted sugar is just enough to hold the sesame seeds and peanuts together and should not stick to the parchment paper when cooled. I had no problems at all. In fact, I even reused the same parchment paper for a second batch.
That said, if you are using a larger tray, you may want to grease the parchment paper lightly with some butter to prevent any spill over of the melted sugar directly onto the parchment paper from sticking to it.