Total cost of a system (including rework and repair) over its life is determined by the choices you make at the very beginning of the design.
The idea is to very carefully consider the design choices before going forward, understand the requirements, ensure all these things are really what you want to have, and then take *very* careful aim at your foot before pulling the trigger.
Max, I think at least 10 very tighly packed equipment housing that I have produced over the years have suffered from a very drastic gotcha.
How to get the magic inducing agent in the box.
I seem never to learn but I build the electronics to fit the box and test with a bench power supply and then find I have forgotten to allow any space to mount a power supply in the box or even leave enough space for a power connector to the box.
Max. all you have done here is proved two fundamental laws:
1. Anything that can do wrong, will go wrong (Sod's law or Murphy's law)
2. The first 90% of a job takes 90% of the time. The last 10% of the job takes the OTHER 90% of the time (This one does not have a name, though I'd be pleased to call it Ashton's law....I just call it the 90% principle)
Aside from anything else, it's always pleasing to note that I am not the only one affected by these laws.... :-)