Okay, I'm no longer sick and it's not a holiday, so I finally have half a minute to actually respond to things! Woo!
Thanks so much for all this detailed feedback, Fred. I welcome your 2¢+ any day of the week. Looking at Endure again reminds me that following through on the analog-made metaphor actually takes quite a bit of careful work, and I'm not sure that the end product is exactly what I'm looking for. Not sure Helvetica Neue or Avenir Next is quite what I'm looking for either, of course, so I wonder if my next step might be to figure out what the overarching style might need to be – black-and-white photocopied, maybe? – and see how different typefaces work with that. Whatever the case, your post probably talked me off the ledge from just diving into using Helvetica Neue and hoping for the best. :)