You fairly handy with some basic hand tools? If so find some tubing with a 1" ID. Or even bend some soft 3/32 thick steel around a 1 inch diameter form to form the material to cut some bases from. Then hack out a couple of base "patches" and cut a cross slot in one piece and a longitudinal slot in the other. Solder a 3/32'ish thick blade into the front and a piece of the same plate in the rear. Glue or soft solder the resulting rough sights to the barrel and then cut a narrow slot in the rear with a jeweller's file and test. Adjust the rear to one side or the other with the file to compensate for windage and file down the front blade or rear cross plate as needed to set the elevation.
All in all once I found the tubing the hacksawing, shaping and fileing would take me about an hour. The soldering about 10 minutes or maybe 20 if I scuffed up and soldered the bases and stuff to the tube directly. Some touch up blueing to darken things up and yer done. All in all it would be a pleasant after dinner job if you're decently handy with some tools.
I suspect that given what you're doing this might be a lot easier and faster than trying to find stuff to use that does the same job and then paying for it.
