Just acknowledging that I’ve read and appreciate all the helpful suggestions. I chose the locally-owned home improvement store to do this because their customer service is beyond great. They will do whatever it takes to satisfy the customer. Their written bid was the most comprehensive by far. The windows are from a regional manufacturer called Prime Window Systems. Their engineering and design documents are published online. The windows meet or exceed all industry standards and have lifetime warranty. Unless I move up to much more expensive Andersen or Pella wood windows I don’t think there’s a better option in vinyl. The install contractor checks out fine, nothing of note that I could find. Licensed, insured, etc. We’ll see how this plays out.