I will be finished with my Wilcox shoe experiment with the 19A this morning. Would have been finished last night but the 1/4"-20 tap went missing.
Fwiw, cut the head off of a 1/4"-20 SS 3/4" bolt and cut a groove in it for a flat blade screw driver. With the spare 1/4"-20 bolt I was nearly able to thread the shoe, which is aluminum, but not quite, need the tap. On a side note, Wilcox's original threading is definitely off center and canted, but I am not going to fix it for fear of trashing the shoe, which is like $60.
JPK