I have never done orange peel but have always admired the pattern. Are they having you assemble the same way as any other curved design by pinning in the center then at spaced intervals? That is the only way I know. However there is a product on the market called a curvemaster. It is a special foot for sewing curves maybe that might help? Here is a link
http://www.justcurves.biz/
Welcome to the board too!