Youve got the right idea. Your only issue to separate out is that you are approaching the sale nuc and the mating nuc as synonymous. They are not.
Pull excess bee power out into mating nucs. Pulling power is not limited to the hives, it includes pulling power from nucs that are already out. So long as it exists keep pulling it and making more, it is a continuous process, all season long. As the queens are made and mated, recombine the good ones with the failed ones into the sales nucs. You do not grow your sales nuc, you build it, and the build is no more than just a few days before releasing.
You do not need to graft. Timelines are significantly shortened and success rate is much higher if you do. But it is not essential. Some suppliers buy mated queens, introduce her to the nuc then sell the nuc soon as she is out a week later. That is actually how many of the big quantity nuc sellers are doing it, they use bought mated queens.
To make your own and to keep it simple, just: Pull and set out, pull and set out, pull and set out, recombine-build and sale, Pull and set out, pull and set out, pull and set out, recombine-build and sale, Pull and set out, pull and set out, pull and set out, recombine-build and sale, .. and so on. Every week and all season long.
Stop when the bees tell you to stop, which is when they are not making excess power anymore or the mating nucs are failing more often than succeeding.