I'm piecing one right now, and was wondering the same thing. Most of mine I press to the melon, but still have questions about it laying flat. I'm piecing this for a friend of mine, now I know why she didn't want to do it. It's king size and it's been a lot of work...I have clipped some of the arcs but don't see much difference in the ones I do not clip. She is longarming it so hopefully it comes out great...No problem with shadowing at all..