mebond

yes, using CLS

Hello dcbear78, yes this will be off camera TTL...nikon d810 and nikon speedlights.  I think manual flash will work if I do not vary aperture or ISO, since shutter won't affect the flash exposure.  However, if I end up adjusting aperture or ISO I would have to adjust manual flash output.  Not a big deal, but my inclination is to try manual exposure and TTL flash based on all this input.

Really appreciate the serious thoughts expressed by the group...

Thanks for the advice!  I guess i will go manual...I was hoping to take the pics right as the sun was coming over the horizon so I wasn't fighting a lot of ambient light, and could get the best background.  I thought about the wind...may ditch the softbox depending on conditions.  I can have the strobe close so I trust power won't be an issue.  Ambient light changes rapidly just as the sun comes over the horizon, but I probably can keep up with it.  Since the window is a few minutes I was hoping for a "fire and forget" solution.  Sounds like it will be more trouble than its worth.  Again, appreciate the help.