Step 4: Surface Prep and Finish
Clamp the two halves of the top together again and sand the edges to try to make them as symmetrical as you can. I used a mini-drum sander bit for my electric drill, but sandpaper on a curved surface should work well, if slower.
Orient the top pieces in the way they will be assembled (one top piece has to flip over and join with the other at the diagonal cut). Mark or somehow assign which is the top side and sand with progressively finer grits of sandpaper until it's as smooth as you like it. You may wish to sand the bottom to a medium fineness---the stain applies easier to a smoother surface.
I didn't do this to mine before I stained it, but if you want the edges to match the top, apply the wood edging to the exposed edges with a heat source, either a clothes iron or (possibly---I didn't try this) a curling iron. The curved surface of the curling iron may work better on the concave curves.
I really liked the look of colored stain for this, so I chose a blue-tinted Minwax stain. I stained the bottom sides first, the the tops, and repeated for a total of 2 coats each side.
I then applied 3-4 coats of water-based polyurethane, sanding between each step. I poly'd each of the surfaces which would be seen, including the "front" of the corner support stand.