First; thank you very much for the feedback and kudos. We sincerely appreciate it!
There is no “standard” for best by dates on frozen dough, or any other products, for that matter. The FDA is currently reviewing best by, best before, consume by, and expiry date practices. In large part the concern is for excessive food waste contributed by arbitrary expiry date practices.
To certify your best by date by BRC standards, you would need to provide sufficient fresh and frozen samples of the course of the targeted shelf life period, to an accredited laboratory with qualified sensory panel. In brief they would test aged samples and fresh samples at intervals to determine if there are any differences. If the panel detects differences, this will most commonly also be accompanied by standardized descriptors of what they agree on tasting. Most trained panels are about 15-20 trained panelists, lead by a trained sensory scientist. As you an imagine this is a significant investment. For analysis over a 12 month shelf life, it might cost as much as $15,000.
As your dough is not intended to be consumed raw, and has a baking kill step, any expiry date you put on it becomes about the integrity of the quality you stand behind. It becomes your reputation.
Although I understand your empathy with smaller retailers, even they will likely have at least monthly purchases through their distributors. If they cannot sell the inventory in 1 month, either they are purchasing too many for the demand in their area, or the product is not of quality or interest to that community.
Perception is the reality people live in these days. I personally believe 90-180 days would be more than reasonable. Some people might look at 1 year shelf life and believe you are hiding chemical preservatives that will poison them. Complete unfounded exaggeration, yes, and it is in that sort of perception reality, and social media rabbit holes, that people put stock in these days.
Ascorbic acid will help strengthen the gluten to improve results after the freezing process. Again, cooperative testing, even over a brief freezing time period is beneficial for you to see the direct effect and ensure you are getting value from the addition. More is not always better.
in a par-baked product what you are looking for are emulsifiers and or modified starches, that will reduce or retard starch retrogradation, which is the staling effect.