I'm a long time pro builder and teacher and must confess I don't read or evaluate what home shop methods might work. What I can say is that really accurate fork alignment is a bit of a process. I'm also a painter and have found the majority of frames that have come in for work were not that accurately built. Well at least not up to top American frame building standards. The blades need to put the dropouts at exactly the same rake (the up/down distance) and equidistant from the steerers centerline (the same side to side distance) . In addition the flats of the dropouts need to be parallel to each other and the blades + dropouts need to be the same length so a wheel centers. If any one of those are a bit off, it can prevent a wheel from being in the dead center.
My fork fixtures are very accurate and I have to make sure when the steerer is tightened down, the fork is not twisted. The fixture will tell me how the fork needs to be bent. I take the fork out of the fixture to bend it by holding the steerer in my bench vise with a wood block and pull whatever direction the blade needs to move. This is a back and forth process until both the up and down and sides put the dropouts right where they belong. Then I take my Campy H tools (dropout alignment tools) and tweak them until the H tools Cups match each other. Now I can use a true front wheel to see if it centers. An advantage of a 1" steerer is that sighting down the steerer it is easy to tell if the rim is a bit to one side or the other. If it is off, I file a bit out of the dropout slot until the wheel centers. I never start to file until all the other checks show perfect alignment. (By the way there is not such thing as "perfect "alignment" but on a fork I would not be satisfied if something was more out than just a couple of tenths of a mm.)