It isn't snarky. It is a reasonable question, and something that has been troubling me for some time in my own search for a new 4x5. I'm trying to figure out why we quibble over minute differences in lens resolution when we don't quibble over camera alignment. In photographic situations requiring true parallelism of the standards, it doesn't take much to obliterate lines/mm.
As Drew pointed out, the weak link is generally filmplane. If you're worried about the camera being square and parralel, don't - just get a good Sinar or Linhof monorail and be done with it. The final arbiter is the groundglass anyway - this is why GG and filmplane registry is so important.


