Tim,
What is the "audibility control" you want to add to Meyer and Moran? As far as I remember they already had one and were happy with it!
It was suggested here recently that M&M was invalid because it lacked a control testing the ability of the participants to hear subtle differences known to be audible. While I agree that would be a good thing to add, I seriously doubt the results were compromised by its omission. Lots of trials, variety of systems, listening material, a broad variety of well-screened listeners from civilians to audiophiles to pros...there was a lot of "control" in the study to avoid the hearing impaired and to compensate for individual weaknesses, just not that one in particular.
Tim