Hi Colin, judging by the title I was expecting far more of a tighter image, building on that in-your-face title.
Is f/8 shooting wide open, if so I might go to f/9 with that rig/set up, pushing the ISO but also bumping up your SS.
Overall it's bit dark, probably by about a stop and you are just on the cusp of letting the light 'scalp & form' the subject. Both Contrast & the Blacks are dominating things, so the detail you captured isn't being portrayed as well as it could be. You really want to maximise that histogram to gain as much data and if you have to darken the image so be it, but probably only by a third of a stop which is nothing.You also want to get as much separation between the two, so it pops.
I think if you were to revisit the file you could do a lot more with it, just with some simple tweaks. Also be careful with too low a SS, you want to avoid Pixelshift.
TFS
Steve