Though -- lol -- I may need to start another thread. I put this all back together and the focuser tube rattles in the contraption that holds it. I can tighten the screw to tighten the tension, but then the focuser won't go up and down. What gives? Argh.
Yes, indeed, you use the torque on each of the 4 screws to
a) take up the slack,
b) set focuser knob friction and stiction.
So snug up each screw a little at a time, then feel the draw tube and rotate the focuser knob and decide to tighten a bit more of to loosen a bit. The final set point of these screws for proper tension will be on-the-order of 2-3 degrees of rotation on the screwdriver body.
Do not be surprised if it takes you 2 or 3 nights before you get it to the tension where "you never need to touch the screws again". And when you get to that point, you an fix the screws with a tiny drop of nail polish on each screw to hold it where it is.