I made the sight-adjusting tool from some scrap 1/8" thick angle-iron. I cut a piece about 3/8" wide and 2" long, and left one end about 3/4" wide so I could grip it easy. Then cut a "V" in the skinny end to go over the post. Then took it to the grinding wheel to knock off the rough hacksaw edges and to "skinny" the two points left when I cut the "V". I had to adjust the distance between the points with a small hammer. I ground a little off the wide (handle) end so I could store it in the fake gas tube under the barrel (along with the original trigger spring). It took me about a half hour.
Some people recommend using sharp-pointed tweezers. On my gun, that would have worked once the post was loosened up. It was glued (cosmoline? rust?) in place.
It turns easy now.
Regards.