On the advice of a helpful reviewer, I re-shot some of my "guy with binoculars" images. This time, I lit the background for better isolation. Of course, I also took a careful look at the first batch. I still wasn't getting the lighting perfect- wisps of hair on the top of my head were getting blown out along with the background. This means too much light was bouncing off the background, and overexposing my hair. As a fix, I moved my mark a bit farther from the background, and this did help a bit, but I can still see slight traces of the problem. I think I need to increase the background-to-model distance a bit more. Here's what I ended up with for the re-shoot, though. (I also dug out my jacket!)
Notes on the lighting: I went from 2 background lights to one, placed directly behind me, and aimed straight back at my background. I used my other two lights as key and fill. Key was a socked beauty dish overhead and a bit camera right. Fill was a shoot-through umbrella about waist level, camera left. (With one light I was getting shadows and uneven lighting on my face.)
If I do a re-re-shoot:
1) Bigger key. (I have on order an Alien Bees PLM mid-size parabolic silver bounce umbrella with a diffuser attachment. It's much bigger than the beauty dish, and my give me enough wrap to replace the fill light with a reflector and put the second light back on the background.) If all else fails, maybe a 4th AB400 will do the trick.
2) I'm using the little metal reflectors on my background lights, but they don't spread the light very much. I will try to even out the background by using two umbrella reflectors instead. This may also mean I won't need gobos to block their spill.
I do get the feeling I'm closing in on finding one lighting setup I like, but I'm not quite there yet. Of course, once I do find one I'll start looking for another...
While I was at it, I dug out another prop. My Glock model 30, a very compact .45.