So far in my short making career I have stressed a lot about enclosures. For this project alone I have over a dozen sketches of five different designs from "Eberline Style" to "The Suitcase" to "Sample Analyzer" with crazy ideas like levered lead doors and smooth integration of USB and SD slots with case and a compartment for calibration controls--all of which are waaaaay beyond my current skill set.
That was where I had stalled out on this project until I recently finished Adam Savage's book, Every Tool's a Hammer. One of the points he makes in it is to plan to build something multiple times before you're done with it, iterating as you go. Another point is that one can (and often should) use cheap, forgiving prototyping materials to make screwing up cheaper both in monetary and momentum/emotional terms.
That's about when I decided to simply bolt the bits of kit I have assembled onto foam-core posterboard.
Many holes need to be aligned? Punch pilot dents with the standoffs attached to the circuit board and drill them with my fingers and a drill bit.
Did I misalign a hole? Meh, ream it out. It's just foam.
Will this layout fit in my project box? Trace the box on the foam board and pretend it's the bottom or top of the box.
Measure twice, cut once? When you have 10x more planar material than you need and cuts are just a knife stroke, cut twice.
It turned out OK.
This one shows the nylon standoff in the high voltage section with the traced outline of the case.
An overhead view:
Note the gap between the WiFi and battery modules. This iteration helped me notice some layout constraints, like making sure the wifi module can slide in and out of place, realizing the SD card and RTC battery slots will probably be blocked by the sides, noticing that the some of the wiring will be a bit tight on the sides, and thinking about alternate layouts that might fit better.
It's also nice that Version 1 is just a little wiring away from being done. :)