Part of your difficulties might come from inadequate use of the flashmeter.
The dome has to be extended and pointed toward the camera to measure the overall light. ( I see that you corrected that in the last images you posted)
When using it with the dome retracted, the light sensor has to be pointed toward the light sources, and you take a reading for each source to figure out your lighting ratio.
As for color balance, I just balance by eye.
If you shoot for printing, you've got to be obsessive about color balance.
For web viewing experience, the individual monitors varies so much that nobody sees the same thing. I've never heard of a porn customer runing color-calibrated monitors...
Most monitors have factory default of 9000+K, so I do all my color correction at 9000K.
At the beginning of each set I take, I ask the model to hold a white cotton towel in front of her.
I use that pic to white-balance (a rare requirement). I prefer that to using a white piece of paper.
I shoot w flash (Profoto Acute2 1200), 5600K
I use a Sekonik meter like your, but the model without the spot attachment. I adjust my ratios, and my overall exposure.
I cross-check the exposure on the histogram (I have the post-shot camera display set to Info all the time) to make sure my dynamic range covers most of the camera range.
If I want to shoot a lot of movement, I need a *fast* recycling time. To do so, I open the lens and shorten the flash energy. I always shoot at 1/200th of a second.
Then, the modeling lights of the flash will give a clearly pink tinge to the image (tungsten halogen is a 3200k while the flash heads) because the ratio of 3200k light to 5600K light gets higher. Then, I use in-camera color balance on a white cotton towel.
Somebody remarked that the laundry detergent whiteners (fluorescent stuff) might screw-up my color temperature readings under flash, but it does not seem to cause me any problems. In fact, it might change the relative color balance between the brightened clothes and skin. I'm shooting for the web, it does not seem to matter very much, so I never dwelled into it more. If I shoot for print, that'll be another thing to do. Beside, lots of white paper contains brighteners too... As for my Kodak grey card, well, it's now grey on both sides.
If you don't have a flashmeter, there is a relatively easy way to set exposure (this camera is WON-DER-FUL!) . It'll require some trial and error, but it works.
Shoot on a large white object (I really love the towel... :-) )
Then, check the histogram.
The values at the extreme right of the histogram are the white areas of the image. IF there is saturation, i.e. the histogram spills out to the right, and you have a bunch of flashing pixels on your image display, reduce your light or close your lens. Bring the brightest pixels nearest as possible to the end of the histogram, but not completely on the end (because you'll saturate pixels)
Then, you have the widest possible dynamic range of information in the picture. (I dunno if it holds true for all colors, though; that's why I think I get better results if I close down by 1/3rd stop from saturated)
To get a satisfying setup usually requires taking three to six images to get the perfect setup. Easily done in 30 to 60 seconds.
To check your ratios, use the same technique, but use each flashheads independently, and angle the towel perpendicular toward the flash head. Take one final reading for each light source.
And another trick. Textbook-perfect exposure is not necessarily what is right... Overexposed pics sometimes makes the skin look younger, less imperfect. Shave 2 years off a 25 y.o. girl by overexposing 1 stop... :D
The viewer doesn't give a damn about textbook-perfect exposure; he want to experience, to feel something...
... but don't overexpose the skin of a beach bunny in a tanning session. :D