complex metering and multiple light sources... (troubleshoot)

[Dikaiosune01]

I'm using Hp5, at Ei 200
I'm also using a sekonic 758D.
I'm using a Metz 58-af1 flash gun


Situation / objective / previsualization:
the sun is behind to the left, and is being used as a hair light
a flash is in the fron to the right, and is being used as a fill light.
My objective is trying to render the background (sky + clouds) darker than the subject. (i.e. portrait)

My process + problem:
Metered the sky (using a reflective spot meter) and added two stops to render the background nice, dark and moody (the way I wanted)
(example: meter read f/11 1/250 --> I dialed in f/22 at 1/250)
THe problem, i'm not sure how to dial in my flashgun to get the correct exposure for hte subject

solution #1
used the guide numbers, to dial in the exposure.
(example (at power: 1/-1/3, distance is 1.9 meters (which is the distance from teh subject)))
problem #2: is when i then change my meter to reflective it is reading a very weird value: (i.e. 1/250 f/5.6). Which is a far cry what I have already dialed into my flash gun.

Do I trust my guide numbers or my meter? Shouldn't they match?

 

[tim k]

I'm wondering if you switched your meter to flash mode.

 

[benjiboy]

The Sekonic 758D if put onto the cordless flash mode will tell you what percentage of the light present is daylight and how much is flash, if you give the meter to the sitter and ask him/her to point the incidental light dome at the camera and press the button, fire the flash within 90seconds and by scrolling the wheel on the meter you can balance the desired proportion of daylight to flash. Watch this http://www.youtube.com/watch?v=ozHMjxJbNQo.