When I was having trouble with the rim blow when the interior temp got over 80 degree F, blowing the horn, cooking the horn relay, and the current flow weakening the coil spring under the horn contact in the turn signal . . . I managed to get the steering wheel off by wiggling it. That got me to the lock plate, which needed to be compressed to get the circular wire clip out of its groove. I managed to position the power seat such that I could push down on the lock plate with my feet, as I got the wire out of the groove and out, to release the lock plate (and then the turn signal switch assy). Just needed a small screwdriver to pry it out. Reverse procedure to re-install it. Didn't know about that fancy tool back in the middle '70s! When the circular spring clip decided to reside elsewhere, I got a paper clip and bent it to size, which worked.
As the columns were made by Saginaw, I found a circular spring wire clip in the GM parts book, later on.
This was on my '70 Monaco Brougham tilt column.
CBODY67