It should not be that crowded during the day on weekdays. There will be people coming for HHN, but by and large, the locals who come for midweek HHN are not there during the day. Some people who are making a trip for HHN will be in the parks during the day, but if they’re smart, they will limit that time or they will be hurting and exhausted halfway through the HHN timeframe.
Moat US-based families will not be vacationing that week because it’s too close to the start of school. There may be some international families, though. Weekends will be crowded, and expect IoA to see a bump in crowds on HHN evenings, as people without HHN tickets go to the open park. We were there for HHN around that time last year, and daytime crowds were quite manageable. Even weekends during the day were much lower than summer crowds.