I’m probably not the expert John seems to be. But my personal opinion is that the Arri Locaster is a solid choice. I’ve used this for interviews, by itself, as a key light for interviews. With the Blackmagic camera and the a DSLR (such as the 5D), the need for a full light kit is already diminished. I used the Locaster with the 5D MkIII in a room with a lot of natural light. I couldn’t have been happier. I would still bring a case of filters, diffusion and perhaps a roll of ND to help control the natural light in whatever room you are in (or a portable diffuser/reflector for outdoors), but outside of that , I think you’re on the right track.