I'd still set the exposure for the light as the skin is the more important target... the light could be metered on the exact opposite side of the point of incidence.
PHYSICS BREAKDOWN!!! Light (a series of photons) strikes a surface at an angle, the angle it leaves matches the angle it impacts the surface (angle of incidence). The surface affects the light after they make contact.
Since the guy in the vid is measuring the leading side of this transaction, he's getting the full weight of the light. The jewelery is reflective, which means it transmits more of the light after the transaction, so the parts of the image where the jewelery are will actually expose correctly at f16. She will actually be slightly underexposed as her skin is less reflective than the bling.
To get a more accurate measure, shielding the meter from the light itself and pointing it toward her from the direction of the camera would get you a reading after the transaction at more realistic values. A series of readings would get a sample that you could then make informed decisions with based on the differing reflectivity of the components of the subject being captured in the image.
The light meter is specifically set to expose an 18% gray card correctly from light you're pointing it at -- at the distance where it's being metered (remember our inverse square laws?). 18% is not an arbitrary value, it's the
reflected luminance of most caucasian skin. Her skin being just slightly darker will expose very slightly below that.
Cool jacket though
This is how I shoot, but in digital, I tend to look at 5 zones: dark, mid, light -- and the commas between them. I use them to target my 3-way color correctors later in the process.
http://www.luminous-landscape.com/tutorials/zone_system.shtml
http://www.colorgradingcentral.com/wp-content/uploads/2011/07/ansel_adams_zones_system.jpg