At what point would you no longer offer adjuvant radiation for adenoid cystic ca of the head and neck?

While the traditional start within 6 weeks is embedded in our postoperative management algorithms, and seems very intuitive, even this has little evidence to support it; though for SCC there is some literature to support the overall "package".

Additionally, this is used to argue for the best outcome...

Almost never! Only if patient is unfit to be treated or they refuse.

Good question. Probably 6 months.