I've now finished constructing the simple basic model that I cooked up in Sketchup and Pepakura and actually it did not give me as much trouble as I thought it would. For the most part I stuck to the patterns provided and had little trouble getting them to fit. I think this may have been helped by the fact that I chose to work with fairly thin plastic sheet, which tends to negate the 'corner' problem that you can have with this kind of project; namely, how do you attach the pieces of plastic to each other? Do you do a simple butt joint (as in woodwork), or attempt something akin to a mitre joint i.e., trying to join the two pieces edge on with no overlap. It may seem a small matter, but it can make a world of difference if you get it wrong, especially with thicker plastic sheet and you could suddenly find large unsightly gaps, or ill-fitting pieces no matter how accurate your cutting.
With thinner plastic this problem becomes a minor matter, but you gain extra problems, namely a lack of strength and rigidity in your model. As indicated in my previous post, though, balsa wood can be used to brace the piece. Another problem is glue, go easy with it on thinner sheet as too much glue simply melts or distorts the plastic. It happened a couple of times on this piece, though it is not very apparent in the pictures, but I have since filled a couple of gaps and hollows with Plasto which I can easily sand back.