After doing a bit more research on portraiture, I have been experimenting more with my lighting setup. I finally clued in on the importance of a hair light, especially on a darker background. For this portrait, I positioned my first flash in my large (42") Softlighter, on 1/2 power as the main light source. Then I used my second flash on very low power without a softbox as hair light above the subject. I pretty much extended the lightstand as high as it goes and angled the flash to point straight down. As fill light, I used my reflector, placing it on a chair across from the Softlighter, pointing - just like the primarly light source - towards the subject.
The problem with this setup is that obviously I don't always have an assistant that can hold the reflector like I want, or even a chair that I can lean the reflector on - which is also quite wobbly and hard to direct properly.
So I went shopping on Ebay. Not for a portable chair, but for a boom arm. This way, I can place the second light stand across from the first one and hang the reflector from there. The boom arm will then reach over top of the subject. I also added a clip that I can attach to the lightstand that holds the boom arm, and I will clip the reflector on that.
In this drawing I tried to show what I mean with "across from each other".
I am planning on getting a third flash, and a third lighstand (one with double hinged legs that folds shorter), to act as either fill light or background light.
As for the importance of hair light - I'm a convert. It actually makes the whole thing easier, with a lot less post processing.