Painting should be pretty simple - 2 or 3 layers of wood glue to smooth out the texture and remaining seams, primer, base color, highlights & shadows (weathering), seal. Since it needs to be heated to make it fit the staff to assemble it, I can't really paint it I am afraid. I'll provide a few extra Worbla scraps you can hide the screws under (unless you want to wrap the handle in leather) or sculpt a smoother transition between the worbla and the bottom part. If you want to be certain, put a screw or two in. Once it has cooled off, take out the staff and apply some glue (simplest would be hotglue, I'd probably choose a 2 component epoxy glue or plumbers putty - anything that fills out hollow spaces a bit) and put it back together. To finish you will need to heat the bottom part, insert a staff (wood, pvc) and press the edges against it to make it fit. I have to admit when sculpting for the tutorial I didn't check any game references and decorated it mostly freestyle the way I thought it would be fun to paint/dry-brush for a nice effect - but if you want it it's ready to ship. I have the one I did for the tutorial ready.
Well, since that Dragonpriest staff is on your wishlist.
