matraina

I've still got on my list to make a memory quilt out of my niece's clothing for my great niece. Here's my question: I wanted to make the disappearing hourglass. I've ironed light interfacing on all the clothes I'm using and plan to cut them into layer cakes. I bought a solid white layer cake and will sew them according to Jenny Doan's tutorial, with a 10" square out of my niece's clothing to a 10" square from the layer cake. What I'd like to know is, will I also have to iron light interfacing on the layer cake pieces so they will be about the same weight.

Thanks, everyone.