Great pictures. BTW, I pulled out my version of Factory Assembly Manual 1947-54 and I found that diagram with in minutes but I swear it was not in it earlier!!
All my attempts have been from about 2 o'clock threw 6 o'clock to 10 o'clock in removing the wheel. I never worked it from the top or at 12 o'clock position -- I hope and I am expecting the '54 button has that little slot to work from. W/out your pictures, I would have never turned the wheel and tried it from the 12 o'clock position.
Thanks bunches! I will let you know my success.
Temporary goal is to put a smaller wheel on until I shorten column. My big arse belly has stopped me from finishing the seat upholstery. Since my butt does not have the same padding as my belly, I need some room from the smaller wheel so I can add the upholstery foam (to plywood on top of the original seat frame). My butt needs something more than furniture moving pad and plywood base.