Thank you for clarifying that. I thought it was about 30 minutes regardless of opening time. But still it seems BOG and park goers will enter at roughly the same time on an 8am opening. I only ask as I had the same idea as op.They don't automatically do that.
Only on days when MK's "regular hours" open time is 9:00AM (including days with 8AM EMH) do they let guests onto Main St. about an hour early (8:00AM.)
On days when MK's "regular hours" open time is 8:00AM (including days with 7AM EMH,) they let guests onto Main St. about 10-15 min. early.