Just be aware that much of the available literature/pool care books out there are full of misinformation ...........

Taking care of a pool is not an exact science. You cannot know precise measurements of things to put in a pool that will take you to a precise reading. It just isn't possible.

Relax a little. I think you are making this harder than it is by worrying so much about the precision of everything. We don't want you to drive yourself crazy!