@timtam, I am going to have to experiment with your method of button combinations for exposure lock and autofocus. Sounds like a versatile system. I simply have mine set up to autofocus with the half press and then use the button on the back for exposure lock. The problem with this is that I find myself constantly having to change the autofocus mode between single and continuous.
Do you use other metering modes other than spot? I find spot metering to be “harsh”, going to extremes in both directions, blowing out highlights or grossly underexposing the majority of a scene.
As for TTL, I do very little with flash so have probably done less experimenting than you have done already. I do find that the flash never seems to make my images bright enough though (with bounce flash), so I find myself bumping the flash exposure compensation to +1 quite often.