We bought a hobby media blaster....looks like an airbrush....gonna try and see if it takes down the roughness on that shapeways nylon...ill let you know if it works....will that fuselage fit in your tumbler? (i think you got a tumbler right?)
i'm gonna try fine glass beads, aluminum oxide, garnet sand, and baking soda...i'm guessing baking soda will be the mildest but that nylon is tough.