I just prepared a chassis myself today for a friend of mine ...
I bassically followed this :
-I Use 320 Emery paper
Before applying CA I use a black marker around the edges and it makes a great finish. I tried different kinds of marker and I found the "Shapie" style marker leave a thick residue, I since then swithed to a Avery Marks-A-Lot with the bif wide tip, I find the ink is much better and not as "greasy", dries real fast. dont use the marker over itself just one good run all the way around the chassis.
I used different slightly different way of applying CA, I put a few drops of CA on a Q-tip and run it in the lenght of the edge all the way around, it works but ill try the drop method mentioned in the CRC article the next time I do one.
I round the battery slots using a Dead 3300mah or 3800mah cell wrapped with 320 Emery Paper. file carefully until desired depth is achieved.