First attempt at OFC - my lads

Hi All,
I've been lurking here for a while now trying to soak it all in.

I need some pointers please on how I can improve please. This was my first attempt with my boys at OFC. Something I need to remember are, shoot at f9 or there abouts not f/4.5. Watch out for vignetting.

My setup was a 580 sitting on a mantle piece about the boys eye level shooting at a cheepy ebay diffuser. This was located left of camera. Had a 430 on the floor behind the boys shooting up the wall to white it out. Hence the falloff towads to top corners.
Setting for the shot
580 @ 1/2
430 @ 1/8
40D
70-200 f4
iso 100
f4.5 (don't ask. I don't know why)

http://farm6.static.fl​ickr.com …72187788_030b2d​5d7f_z.jpg

Any help and pointers would be most appreciated.

edit : I forgot to ask to leave the gloves off please. Show no mercy thanks
edit II : deleted image and moved to critique where it should have been.

I'm thinking that you could avoid the light fall off by raising the flash that was on the floor, to a small stool that is hidden by the boys?

suecassidy wrote in post #11900716
I'm thinking that you could avoid the light fall off by raising the flash that was on the floor, to a small stool that is hidden by the boys?

A simple but effective suggestion, thanks Sue.

I forgot to ask to leave the gloves off please everyone. Show no mercy
edited in OP too.