Marc, I too am a creature of habit. Normally I shoot manual or aperture priority. However, I soon realized in order to maximize sharpness with the Hassy I needed to change my shooting style.
The following only applies for handheld candid and walk around photos.
Based on what I was shooting or about to shoot I would first set my iso. For daylight shots I would use iso 100 or 200. For inside temples or night shooting I set iso to 800 or 1600. Somewhat subjective.
If I was shooting people I used continuous focus. If I was shooting static objects, I switched to true focus to compose my shot.
The shutter speed I chose was very subjective. I would take into account the focal length of the lens, if my subject was moving, if I was moving and whether I could steady the camera on something. For example, with the 80mm if I was on a trolley car, I would use 1/500 sec or faster, if I was hand holding I would use about 1/250. If I used a post to steady the camera, I could use a very slow shutter speed (1/30 sec for example), but for people shots I would try to shoot at 1/100 or faster. As daylight faded I would either increase iso or decrease shutter speed or both. With the 28mm I would shoot at slower shutter speeds.
In general, I tried to be conservative and shoot at a slightly faster shutter speed knowing that it gave me the best chance of sharpness. I was willing to sacrifice a little depth of field in order to increase the odds of my subject being a bit sharper.
Of course, you must realize this explanation is after the fact and because you have asked the question. During my shooting, I was constantly tweaking and adjusting based on what I thought would work. Sometimes it did, sometimes it did not. Hope I have explained this well enough.
Very useful information. I'm such a creature of habit that I've never even tried shutter priority on one of these cameras.
Can you take a moment (when you can) to describe how you determined the shutter speed for any given one of your shots? Did you use the mirror delay at all? 1/6th shutter is amazing, and even if you couldn't make a huge print, the native size of the big sensor should "perceptually" allow a reasonable sized print relative to a smaller sensor don't you think? It's probably important to see some of these as prints rather than 100% on a monitor.
-Marc