Haha, I'll add hamish to the list. I've managed to get the bolt sizes down to something reasonable (ish). I think the first model will have a print volume around 100mm diameter and 100mm tall. The scad file will be completely parametric of course so you could change that to whatever but that's where I'll start. I've decided to add an option for how to define the machine, instead of giving it a bed diameter for the base of what is roughly a triangular base pyramid, I'm adding support for the user to define a cylinder that they want to be able to print. I figure it'll be easier to visualize and people will be more used to this from linear deltas (plus it means I don't need to find a way to incorporate the funky pyramidal print envelope into a slicer).