First time I'd looked at that setup ... looks interesting!
I have the Arca Swiss P0h. For my use with Hasselblad 500CM, 907x, Leica CL and SLR cameras, it's proven quite stable fitted to Manfrotto 190CXpro3 legs with the shorter lenses and Feisol CT3442 legs with the longer lenses/bellows unit. I haven't found much difficulty with droop ... and one of the things I like about this head is that if I do have to use it off the upright angle and a little droop occurs during my sloppiness in locking the ball, it's easy to correct precisely with the goniometers. I rotate the rectangular format cameras through 90° (from H to V) using L-brackets.
My gut feeling is that something like the Cambo Actus, however, presents more sail area and a bellows camera with front and rear standards is always less stable unless it is really well designed (or/and weighs a ton and a half). Vibration damping and overall rigidity become more significant, and probably a little different from the long-lens telephoto on 35mm format type of additional weight due to the distribution of masses and sail area. A larger set of legs and a heavier duty head seems necessary for that setup to maintain equal usability.
I haven't played with a bellows camera with swings, shifts, and tilts in many years. The Cambo setup using my CFVII 50c back and V system lenses might present an opportunity in that regard. But I suspect not this year... I'm still just learning how to visualize and solve problems and get what I want with the 907x.
G