You will find if you make the pieces smaller, that means living with more seams, you could make a ball using water. It's the "bucking board" that you need to make for the different curves. This is what they use for mahogany strip boats, to give an idea what people do for their particular passion. It's much easier with paper as everything is smaller. The same methodology can by used. SO much can be done if people painted their models, rather than insisting on pre-painted .pdf's. Printed parts have their place, in fact, probably for most of the model, but there is a time when going that extra step really makes something unique. Since you use Rhino, you can make any compound shape, cut it into pieces, and use those to make formers. Fill those with a good 2 part steel Epoxy, and you have a permanent plug for making canopies, blisters, etc, you name it. Methods show below can be used with wet paper. A lot less toxic.