Yeas, she's welcome too! xD
I'm into surgical knives. The ones with a metal handle and interchangable blades. Currently I use a 22 for leather crafting. But for Foam I've been recomended a nr. 11 blade. They come 100 blades for a few €/$. So they're very affordable and work like a charm! Imagine a blade so sharp that you can cut 3.5mm thick TANNED leather as if it were 5mm eva foam!
Really scary sometimes. But I'll definitevely keep that in mind, about using razor sharp blades for cutting! Thumbs up for the recommendation!