I did a kitless ages ago and pretty much followed the same as I do for CA or any other plastic. I sanded to 400 or 600 and then 0000 steel wool. All grits as flexi does around and across. Then I used the three wheels of the Beall buffer in the lathe. Tripoli, white diamond and lastly the carnauba wax. First radially, then diagonally both ways and finally lengthwise for each wheel. Clean the blank off between each grit with a clean cloth so you don't contaminate the finer grit wheel with coarser compound as you move up. Turn the wheels at about 1,000 to 1,200 rpm to keep the surface of the ebonite cool.
The "Little Black Number" is a pocket / purse fountain pen with a #5 Schmidt nib. Length cap on 9.2mm. Cap off 12.4mm. 12mm triple start thread.
Pete