Yet Another Steering Problem to be Solved

Hi, I'm new here and look forward to participating.
I'm turning to you, the folks with this wealth of knowledge of the Skyliner for my steering problem.
I have a 57, white over blue, with about 53k orig miles. Everything is original except the Continental kit added about 74.
My only problem, which I've had for the 2 years I've owned the car is the sloppy steering. There is about a 4"-5" dead spot in the wheel at center before you feel the steerlng start to respond. I've changed the control valve without success but we have noticed that the control valve moves slightly when the wheel is turned when the car is on the rack.
It seems odd to me that the valve should move at all if installed properly.
I also believe that some of my handling problems stem from the bias ply stock tires on the car pulling with every gum wrapper you run over in the road. I'll probably change these out soon in order to narrow down the problem.
There seems to be many potential culprits to assign to my problem such a pittman wobble, ball joints, connecting rods and drag link just to name a few. Oddly we don't see any of these with excessive play up on the lift.
Any suggestions greatly appreciated.

You may possibly be able to take a little slop out of it by tightening the tolerance of the steering box. Small 1/4 turn adjustments at a time.
Been a while since I've done any of that and never on my current old Ford. Seems like there was a locked screw or nut on the top of the box somewhere on my '55