Inspirational Lachlan. Did you make those springs yourself, or are they from Deardorff/somewhere else? Also I think I remember a reference to cloth for bellows somewhere - I think it was from you, but could be wrong - was it Spotlight blackout material? I can't find the post. I'm about to start a non-folding 4x5, something light and easy to carry around. I've bought some Huon Pine offcuts from Tassie for the job. Good luck with the rest of your build, but by the look of it you don't need any luck.