Looking for advice on the best camera exposure approach for a sunrise beach shoot using off camera flash and subjects backlit by the rising sun. I would like to expose the ambient background -1 EV, and properly light the subjects. I would also like to control depth of field. Given that ambient light is changing second by second and there is only a limited window of time, I was thinking of shooting TTL, aperture priority mode in auto ISO (while keeping an eye on those values as the light develops), with an exposure comp in the camera of -1 and offsetting flash comp of +1, adjusting to get the right balance. I will be using a d810 with a speedlight in a softbox, and a reflector or second speedlight at low FEC as fill.
Probably a simple question, but hopefully others on the forum can share the best practice here. Thanks so much in advance for the help!