I have seen that sentence sooo many times "Overpowering the sun" Well, how often do you shoot with the sun directly behind your subjec AND with the attention of still keeping the sky dark blue?
What I have found to work great, at least since I mainly use one light, is that I shoot with the sun more to the side and use it as a rim-light, and then the added bonus is that I can use a polartizer since I'm 90 degrees to the sun. If I shoot with the sun directly behind my subject I often go for the flare-type shot and even then I can get some good detail in the background at 400Ws, the issue with power is if you want the sun towards the camera with 2 stop underexposed background and you have both diffusers (of the Deep octa) and the deflector, doesn't happen very often in MY case at least.
I have the Quadra-head mounted to the Octa at all times, it's like just having the Octa, it's soo small and light, about the size of a 50 L, but one third of the weight...
This example is just one of my facebook-uploads so it isn't the highest quality, but hey. (god I miss my mac, it's being serviced) And I wasn't near the limit of 400Ws on this shot. Shot with only outer diffuser. Very hard sun.