I know the manual talks about the importance of proper fit on the rails, etc., but have never understood why... As the kit uppers assembly (which looks like a slide) doesn't move. Perhaps they mean it must fit into the frame properly and slide all the way back, etc. -- that I understand.
The insert in the slide moves (the bolt/slide equivalent) with each shot, but sights, barrel, and upper (which looks like a slide) are one unit stay aligned. Unless pressing the trigger pushes the firing pin block linkage and presses up on the underside of the upper assembly, and there is some play there (so that it doesn't push it exactly the same with each shot), accuracy shouldn't be greatly (if at all) affected.
The manual displayed in the link above appears to be for the 75/85 models. That probably doesn't matter, but I know from experience, that the Kadet Kits sold after the B models were introduced wouldn't work on some of the earlier pre-B models -- as the hammer on the pre-Bs were too wide to fit in the notch at the back of the Kadet Kit, and couldn't reach the firing pin!!
With an early pre-B, if you wanted a .22 conversion kit you had to find a Kadet Kit made for the early pre-Bs! Sort of like hen's teeth. I think I only saw once advertised for sale over many, many years of searching.
(I eventually sold that pre-B, but had others. I think the one I sold may have been one of the much sought-after short-rail models, but I didn't know enough about CZs back then to know it may have been that type.).