Thanks Roger for the reply, it confirmed what I was thinking. I have found someone who sells .5mm 'scrap' offcuts that are to small for them to use. Conveniently, they're the right size for a small box stove! I'll start with those and see how it goes. Will post pics when finished as I'm going to try and combine the best design features of Tigoat and Kifaru in some ways.
Also thanks Roger for replying in mm. Although I'm from America and have a converter I use it make life that little easier. :)