'I think Ed is asking about TTL flash. IIRC the SQA doesn't have TTL worse the CT5 doesn't support the Bronica module. The CL4 does but if the camera won't no use worrying.'
Sorry Nick I haven't quite got the gist of your reply so forgive me if I am repeating myself.
Yes the Bronica doesn't have TTL metering, they way I normally use the flash (which is not that often hence my experimentation and questions) is to take an incident light reading on the subject, set the camera at the specified shutter and aperture and then set the same aperture on the flash. The Bronica has a leaf shutter so it will sync with any shutter speed. This will of course make the flash the dominant light source.
For fill flash I understanding that you open up the aperture on the flash head by 1 or 2 stops (eg: if the camera is f16 then the flash is set at f11 or f8 respectively) which should make the flash give a weaker pulse of light so that the ambient light source is dominant.
Am I correct in my understanding of this is how the Metz 45CT5 or the 45CL4 work? From your reply are you saying that the 45CT5 is not compatable with the Bronica SQA (which has no internal metering system - it is totally manual).