Razors from Ebay usually have one thing in common, oxidised (rusted) steel on the edge. Before any decent bevel can be developed the oxidized steel needs to be removed. Usually either a 1200 DMT or 1000 grit sandpaper is used to remove this. Occasionally a 4K Norton will do the job. Use your microscope to look at your starting edge/bevel. Check every 20 laps or so. What you are looking for is a lack of rust colored spots/pits on the bevel and a uniform texture on the bevel and also on the edge. The 1000 grit range is very harsh on the edge of a razor so do no more than is necessary with that grit range.

Just my two cents,