It's going to get ugly before it will look better. The curves on the grip and chamber portions have to be carved out then filled in with wood filler, and sanded until the desired shapes are achieved. I don't exactly know how mousemuffins does it but when the CA/Superglue is applied it immediately hardens the 1mm board making it stronger and easier to sand.
cut out the corners with a spare cutter blade
My first time to work with wood filler. It shows!!
Will have updates in a few days. Work always gets in the way of my hobbies.