Thanks SchitzCOL I think you scanned page 1 twice and page two does not seem to have finished the explanation.
Either way, the idea is to measure the wear in the shaft and adjust shims accordingly such that there is some plunger pressure on the shaft even at the most worn point. I would suggest adjusting the shims to compensate for this wear can be done by simply trying different shim sizes. Yeah, not as accurate, but good enough. Shim stock is available in sizes from .05mm up. I think .05mm is quite fine, I would start with .1mm and when getting close I would switch to .05 to fine tune it. You will find a point where adding one more .1mm shim is too much, taking it out is too little. That is where I would add a .05mm shim instead. These numbers are just for example, you may find that you need to add so many .1mm sims, you might as well put a .5mm shim to begin with.
Alternatively, you can measure the rack diameter somewhere not worn at all (at the top of a tooth - the teeth tops do not wear because they never contact the pinion, so entire wear measured will be in the back of the rack where the plunger pushes against the rack) with a micrometer and compare with the worn section. That will at least give you some idea what shim thickness to start with. Take a few measurements along the rack. Only shortcoming of this method is that it does not account for wear in the pinion so you might end up with more shims than the numbers would suggest.
I scanned all the pages but in the rush I uploaded page #1 twice, I have fixed it and uploaded the 3rd page to complete the explanation