Each gear is unique, so print one of each (gears 5 and 7 are so similar, they can probably be interchanged). Skeinforge can be a pain, but to get around one bug I found, uncheck "infill in direction of bridges" in Carve. The one pictured was printed on a TOM.
For assembly, I recommend screwing each gear tightly into the center block so it can't turn and place each gear so they are smooth and continuous. The complete stl file is for assembly reference. Once they're all in place, loosen each screw a turn or two until the gears spin freely. Give to loved one.
The OpenSCAD file is fully parametric, so feel free to adjust to your heart's content. It's designed for M3 screws right now, but that's an easily adjustable element.