Advice on putting brushed finish on side flanks with crown guards

For watches with brushed side flanks I use a bench top polishing lathe with a 4 inch Bergeon 6723-240-LP wheel to get a nice brushed finish. However, the wheel is too large to finish case flanks if there are crown guards (like the Seamaster Professional 300m).

Does anyone have tips for the proper tool or wheel to finish that area of the case? Does anyone know how an OSC does it?

Thanks.