Building Fool-Flying Noob
Somewhere I read about you wanting corrugated look. There is I believe not only in packing material but also flooring foam that is ribbed on one side. Some sheets I have are called Selitac they measure about 48" x 36" , more underlay for hardwood floors, it's labeled as 3mm but it doesn't look that thick. The cool part of these flat sheets they have a ribbed side to them so it will bend nice one way and be more ridged the other.