I killed this bull on Aug 31 a few years ago.
He never made a sound - spotted him feeding about 100yds ahead, buddies backed up, set up and mewed as I was up ahead and to the side.
Two years ago on Sept 1st I shot a spike after missing a 5pt with cows the day prior. Can’t recall if that was the opener exactly, but essentially it was the first day or two of the season with a good moon. We had other encounters that first weekend of the season and bulls big and small were already in small herds. Last year, we went Sept 10-20 with a pretty bad moon phase. Much more rain and colder temps. Mid day was much better action and ended up getting my father his first archery elk. So, just in those two years in the same unit, seemed like moon phase didn’t make a ton of difference and if it did it can be mitigated. I’m liking the Mid-Sept dates as a typical date range and maybe shifting slightly based on the moon forecast.