Advice for shooting a large group?

Basic questions regarding taking a large group photo; the shot will consist of about 40-50 people. There are stairs to arrange the group allowing everyone to be visible.

I'm curious to lens choice and possibly lighting suggestions.

I currently have a Canon 60D with a 28mm and 50mm prime. I also have access to a Tokina 11-16mm and Canon 10-22mm.

Of these, which will probably be best for such a large group?

Secondly, the shot will be taken early (~9am) in front of a relatively large building. Most likely the sun will be behind or slightly above (meaning we will be in the shade). I'm thinking bringing in a flash or two to kind of lighten up the eyes and lift any possible shadows.

Any reason not to?

The group will be set up on the stairs in front of this building.

If everyone is in the shade, then that's a good thing. You could use a little on camera fill flash if you want but you could easily get away without it. As far as positioning, I would suggest taking the photo as far away as you can reasonably get and using a longer focal length. IMO, long perspectives make group photos far more appealing (for the most part). It will give more of a "compact" feel to the group as opposed to getting up close and using a wide angle lens, which will leave your back rows looking as if they are way off in the distance. Considering that you are positioning them on stairs, I would also suggest using a ladder to stand on when you take the photo, this will help you clearly see everyones face and keep everyone looking up at you as opposed to having people looking down to the camera (which creates double chins along with a host of other issues and doesn't usually make a flattering photo). Good luck

Thanks for the input. Unfortunately the ladder is not an option. I will be using a tripod though (about 7 1/2 ft - 8 ft).

I will probably take some with and without fill flash.

From another site, I got good advice for getting everyone ready for the shot.

Tell them to look down toward the ground and on the count of three, they look up and smile at the camera and fire off a few shots from there.

Oh and after advice from another thread, I'm just sticking with what I have. Similar advice from you, it's probably best to steer clear of wide angles with these group shots.