The physical mechanics of the rivet machine were a bit of a nightmare to use when working with thicker fabrics. I was really struggling.
Thankfully @Juliette_Lemaignen was able to attach to a block of scrap wood to make it far more usable for me.
I can remove the block again after I’ve finished riveting or we can leave it, so it’s better for everyone. I’ve checked and it still fits on the shelf with the block attached.