Just did a test of a lighting setup I plan to use for shooting a friend of mine. I've been doing it in my head for weeks now, so I set it up quickly while the kids were watching TV and couldn't bug me. The flats are opened up, so you can see the SB-600s.
The little slab of foam core in back made a down and dirty white backdrop (illuminated by an SB-800) that had to be remedied in PS. Since the goggles are the main thing here, the glass needed a huge (apparent) light source to give a nice, full reflection. Mission accomplished!
- Put the flats up higher (they don't need to light the ground, doofus).
- Tape up a larger backdrop.
- Use ring flash. I like the grey b/g here better than the blown-out white shown below, and a ring flash would give a nice shadow in grey.
Most importantly, I would give my kids whatever they drank from the medicine cabinet that day, which made them willing to pose for me.
All the best!