I’m just guessing, and look forward to hearing more educated guesses from people with data on Pandora & once DL opens BUT
I would expect that in August, yes, it will be swamped at 6 and well before, necessitating taxi service to arrive around 4 or even earlier to be able to get into the land itself.
By October, hopefully you could treat it like an AK rope drop or something, arriving at 5. Of course that’s up to you. By then, arriving later might allow you to see the land but wait several hours for the ride. By arriving at 5 you might get to wait 90-120m for the ride instead, closer to 90 on a weekday?. (I’m basing this off the fact that FOP had a 90m wait on a Friday morning last month at 8:50am with a 9:00 open)
Edited to add: I’m going in August but avoiding DHS, I think. However I’m a morning person and might consider going mega-early or returning in September just to go in the early morning hours. I’m so glad they’re doing this because many people won’t get up this early on a typical vacation and it might make the crowds tight but bearable instead of dangerous.