Good idea...I recall early conversion cylinders didn't have the cuts..... and the simplest way to show empty (for me) was to show the empty chamber (left of the alignment pin), then place the cylinder cap on...then insert the cylinder into the revolver and show placement of the aligning pin as the cylinder was indexed and hammer lowered. All with the direct attention of the loading table officer. No-one every disputed this procedure, nor any problems encountered. Easy enough for a person without ATD..
Later, we carefully filed a notch in each chamber as an indicator, similar to what you did with your factory conversion. Of course the 6-shot conversion cylinders all come with the notches today.
If a person did not wish to cut their cylinders, an alternate method is to mark the empty chamber with white-out or white paint, etc and show this one as empty when loading, then show it aligning with the hammer down. Paint is probably abetter option as it is more easily removed with typical gun solvents....W-O can be quite durable (at least so on Mn-Phosphate finish surfaces)
Slim