Head shot practice - How did I do ?

I had the chance last night to take my equipment to our photography club and have a couple of experts comment on my proposed setup for some head shot I'm to shoot at work.

Equipment was:
2 Yongnuo YN568EX/622 trigger on stands with shoot through umbrella
1 Yongnuo YN568EX II/622 trigger facing 1.5x2m pup-up background
1 Canon 7D/622 trigger with 24-105L at around 70mm

The final setup was shoot through umbrella flash camera right (main) at 1/2 power and camera left (fill) at 1/4 (1 stop difference). The rear flash was set at 1/2 and raised off the floor (I might need another flash stand). Both main and fill flashes were about 35° forward of the subject with the main 6-8" above the model's eye line and the fill 6-8" below. All flashes were zoomed to 24mm (for a wider spread of light) and the tips of the umbrellas just out of arms reach of the model.

Using manual and trial and error, we found f6.3 (down from f8) gave an acceptable result on the cameras screen, but a light/flash meter suggested f5.6 which looked even better.

Minimal processing in Light room involved a slight crop, + on the whites/highlights (to blow the white background - should probably up the power on the rear flash), sharpening and a little clarity.

The rear flash was turned round for the black background to add a little rim light.

The corporate head shots I will do at work will be with the white background, but we also tried the black:

IMAGE LINK: https://flic.kr/p/pv3V​FL

IMAGE LINK: https://flic.kr/p/pMdq​Qp

IMAGE LINK: https://flic.kr/p/pMwq​Ps

I think you did just fine on the lighting on both the white and black background versions, with the only potential tweak being perhaps a little more hair light on the dark one.
Otherwise, I would work on is the pose... there's something very awkward about that pose in these tests, so maybe do some research as to the most flattering posing techniques for your particular needs.

Light looks good, yes the head/neck angle looks a bit contorted.

The rim light in the second shot, is a bit low for the subject as you arent getting separation on the top of his head. I think your camera is also a bit low as the neck/chin is too prominent.