Since they are talking about a synagogue from the early Roman period, why not use Roman dates? "A.U.C. 700 to 900" (counting from the founding of Rome in 753 B.C.). Or use Olympiads and get everyone totally confused.
>>but since the Muslim year is about 11 days shorter than a solar year, it wouldn’t be very practical to use.
You defame Isssslahm! I keel you! Durka durka JIHAD durka.