I've re-checked the measurements against the plans I have that came with Jurassic Karp, the measurements for everything else are within a couple of millimetres of the specs and compare well with Karp, its only the cases that aren't at the specs.

~100mm further forward than they should be even tho they are the wide case slots.
With the ~40mm packer I'm still forward of where it should be by about 60mm.