f/8  f/8 and f/8

Some photogs obsess about stuff and swear that round flash reflectors are
much better than rectangle ones at getting a smoother more even spread of
light.  And they'd argue about vivitar vs armitar (they converted vivitars
to a barebulb with a push in round reflector like norman and Q-flash)

Tip:  move back and use the longer end of your medium range zoom.  Your
light spread will be more even and the longer focal length means less
distortion, you don't want the guy on the end to get an oval head, nor do
you want the one up front and center to be larger.