In theory you can work ruby with anything harder or as hard (diamond is worked with diamond), but it's so easy and cheap to get diamond lapping compounds and powders that it's really the way to go. I'd suggest a copper lap rotated in the lathe, but almost any material is ok- acrylic, iron, etc. For pallet faces I would use 1micron diamond, it will cut slowly but surely and leave an entirely satisfactory finish.
I picked this little Russian up and was enamored by the dial. When it arrived I discovered it had the stout Vostok 2209 movement. I found it was a very clean movement and only needed to be adjust for timing just a bit. The dial that had my attention looked to be silver plated copper with a rather dirty looking patina. The dial isn't engraved as I had hoped, but was stamped with the pattern formed during that process. I wanted to make that pattern pop so I painted the entire dial flat black and used thinner to remove paint only from the top surfaces. Was a bit tricky to accomplish but I think it came out great. Next I turned my attention to the hands. Somene had put a shiny black varnish on the hands as contrast, no lume was present. So I cleaned that of and since I didn't have any white paint, I used liquid white out. I know this is probably blasphemous, but it's a totally temporary solution until I get some lume I like. Placing the hands back on was a bit tricky as the fit was incredibly tight and tough to accomplish with my huge sausage fingers. I have a black leather strap on order for it. Very pleased with the results. Thank you for reading this.
May I suggest that you are extremely careful in handling the piece, like zero forcing of anything ever, no free runs of the train under MS power, etc. Chinese mov'ts are especially delicate, they tend to break by themselves easily and do not resist any mistreatment. Very recently I have broken a Shangai one in three different parts, that before counting the rotor that had split in two and the anti-shock spring that left on a shock. A Segull can be just $60 but a Sellita 200 for GBP at 140+VAT is not that far way in terms of price, but deliver much better reliability, and the parts are actually available.