Thanks for all the replies!
Agree, whole heartedly. The more I read, the more I'm thinking they've priced down to bare necessities, to land the bid, vs answering my question of "What would you truly recommend, if building for yourself and the long term". VS is on the list of requirements.
I'm going to request specific models, so I can look up specs, for sure. The common thread on the Nature2 system seems to be consistent. Simply Don't. So, I'll get their recommendation on other options, or justify the need for that 'feature', rather. I'll follow up on the filter sizing.
The design really came out well! They knocked that portion out of the park, from my expectations. It was one conversation, and he only had our survey to go off of (office is about 45 minutes out), so that was what he brought, when he first came to the house. I gave a handful of non negotiable, and left the rest to him.
The metals produced, and the eventual staining are also commonly referenced. I've spoken with two other local builders who came recommended. Both were pretty adamant against salt, with one (coming Tuesday to bid) stating "I'm the owner of this pool company, and I had a salt pool and had a bad time with it, and we installed a great system. We guarantee you won't have issues, like you will with Salt in our area"
A friend of our's built about 4 years ago and I asked them what they would do different. "Chlorine setup, not a salt setup" was the first thing out of their mouth. This was followed by a much larger VS pump, better heater, and lighter color unite.
I'll revisit the automation for some more info. He acted like it was a ton of money, and not that much of an inconvenience, but I don't believe I fully understood what would be required manually, without it. I don't mind turning valves, back flushing, testing, adjusting, etc. I'm just an ol' plant operator (console now, but outside technician for quite a while) so working equipment and understanding optimal ranges is definitely within my wheelhouse. That said, I don't want to skip on convenience/excellence, if its within reach and not excessive.
I've been in a few Gunite spas, as that is largely what is around here. Is there any specific element you're referencing? I'm open!