I would definitely play around with it. Your not going to want to go too wide with 4 because odds are they will move around a bit and you’ll end up with some soft faces. Some key things to remember would be try to keep their faces all on the same plane of focus, that will allow you to shoot a little wider. Generally with 4 kids I would aim to shoot around f/4 but certainly play around. At that aperture you may want to consider moving them further away from the background. Keep in mind the closer you are to them and the further away from the background they are the more bokeh you will get!
I just received this in the mail. It does smell a little like oil based paint, but you have to put your nose up to the fabric. The white and gray is what I ordered so alternating contrast is to be expected. First thing I did was throw it in a dryer with a wet towel to remove the creases and randomize the wrinkles. It's a backdrop of the same quality as the all black backdrop. I expect to be using it in a maternity shoot this weekend and I think it will be wonderful. What I ordered and what I expected. It isn't heavy which makes it portable for other locations, but it means it may not be what some people expect. I'm happy and looking forward to a lot of use. I think it will work for what ... full review