A little practical advise using the TLA30 under a specific circumstance. If your outside, with a fair amount of ambient light, I've had good results using the following procedure:
Meter the shot with your camera in center weighted mode, take note of the shutter speed and aperture. Go to manual mode, set the speed and aperture, then set the exposure compensation dial to minus one. (keep the shutter speed within the cameras usable x-sync range, 125 or less for the aria IIRC)
This works with my mm159, perhaps with your aria, perhaps not............
The net effect is getting fill flash at one stop down.
It's the only way to achieve full at one down with my particular combination (159 and TLA30).
A mite cumbersome, but the results are worth it.
Good shooting,
Joe W.