I'll include a link from one or the extension services on how to store eggs for hatching. It might help you.
https://aggie-horticulture.tamu.edu...e-Cartwright-Incubating-and-hatching-eggs.pdf
This article contains some "if's". We all have different conditions so we can get different results even if we do the same thing. Pay attention to the "if's".
If you store the eggs in "ideal" conditions they can go a long time and still hatch. It is not a case that at a certain point they all go from yes, most will hatch to all of a sudden none will hatch, but it's about hatchability. The longer they are stored the less likely they are to hatch. So your hatch rate gradually drops, it doesn't fall off of a cliff. The further you are from ideal conditions the faster hatchability drops. I store my eggs in way too low humidity and warmer than their suggestions. I can go a week without a drop in hatchability. I haven't gone longer than a week often enough to try to determine what my sweet spot might be with my methods of storage, when does hatchability noticeably drop. It's dangerous to make too many assumptions based on one hatch. There are too many different things that can affect a hatch. But do pay attention so you can maybe detect a pattern in your results when you incubate.
Just because they say you don't have to do something doesn't mean it hurts to do it. You don't have to turn the eggs during the first days of storage. You don't have to turn them during the last few days of incubation, say after 14 days. But it doesn't hurt to turn them as long as you stop before lockdown. Even then, some people on here said they lost track of lockdown and continued to turn them and still got decent hatches. Continuing to turn probably won't kill all of them but it can reduce hatchability. Even though we don't have to keep turning them we tend to stop turning at lockdown because that is when it is convenient for us to stop turning then. So plan what you do so it is convenient to you.
I noticed you do not plan to mail them, it will all be local. I don't know if you will transport them or if your customers will pick them up. In either case the eggs should be well cushioned when they are transported. Excessive shaking can greatly reduce hatchability. I made that mistake once and blame shaking them on a rough country road for only getting 10 chicks out of 30 eggs.
I don't know how many different breeds or species you might have or what your facilities look like so how you store them and keep them straight is up to you. It has never bothered me to get hatching eggs with something written on them but if you are planning on selling or giving away the older eggs I could see why you don't want to do that.
Good luck on your adventure.
It still works on Wayback though.
