Hi Robin,
The video was more to show that all should go in a fluent motion.
Ok here he comes again, no problem
The basic of the hardware.
1 stepper motor
1 leadscrew axle with 2 mm pitch
1 load cell.
Stepper motor full rotation = 360 degrees
With a leadscrew pitch of 2 mm each full rotation of 360 degrees of the motor the spring is compressed 2 mm.
2 mm steps are to large for fine measurments so we prefer avalue like 1 mm or less.
So to get 1mm compression we only have to turn 180 degrees.
If we want to compress 0.1 mm we ony have to turn 18 degrees.
The steppermotor I use has 200 steps for 360 degrees rotation.
100 steps is 180 degrees = 1 mm
10 steps is 18 degrees = 0.1 mm
Are you still with me? 
I put the spring on the loadcell bottomcone and the loadcell now will give a certain value if we would measure it.
The spring is still uncompressed as the topcone part that moves down is not in contact yet. So first basic point is to find that TOUCHING POINT.
Now we can do this manually but turning the steppermotor by hand and look at the loadcell value when it starts to become higher, but we are trying to automate the measurement so we like to skip that manual part and do it fully automaticly to reduce time. Now we have to electronicly find the point where the topcone touches the top of the spring.
We can do that easily by measuring the point where the value on the loadcell starts to rise.
The HX711 lib slows down the steppermotor as each reading takes average 90 ms and we cant speed this up we found out.
So catching this first TOUCHING POINT is the key problem of this combo stepper and HX711.
Am I correct sofar and can you folow the basics of the project?
Paco