One of the most difficult things for photographers to photograph is large groups.
Communication is key to getting the best photo where you can see everyone’s face.
One of the best possible solutions is risers. They are often called CHORAL RISERS.
Now even using these risers doesn’t solve the problems with people’s heads blocking the people behind them in a photo.
No matter how many times I work to get things just right there are always a couple of folks who move and from their perspective they think they are OK.
The two guys on the back row here think they are OK since they can “see” me. What you need is each row to create enough space between people that the space between their heads creates a “Window” space for the people in the row behind them to stand.
Staggering people works, but telling the people on a row to help create a “Window” and have the 2nd row put their heads into those “Windows” can really speed up lining people up for a group photo.
If you don’t have risers be sure to create more space between people.